diff --git a/CHANGELOG.md b/CHANGELOG.md
index 504b5de84..795276f77 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ All notable changes to Bambuddy will be documented in this file.
 - **The K value is on the AMS slot itself, not only in the popover (#2532, requested and contributed by @gyrene2083)** — Reading back a slot's pressure-advance value meant hovering it: the K factor lived in the filament popover alone, so checking whether a calibration had actually taken across four slots was four hovers, and comparing two of them side by side was not possible at all. Every slot card now carries the value under the material name, the way Bambu Studio shows it per slot — on regular AMS units, on AMS-HT, and on the external spool of a dual-nozzle machine. Only a value the printer actually reported is shown: a loaded but never-calibrated slot stays blank rather than inheriting the 0.020 that fills the popover's own field, and a slot the firmware reports as exactly 0 counts as uncalibrated the same way the stored K-profiles do. The label is shortened to **K** with the full localized name on hover, because "K Factor", "K-Faktor" and "Facteur K" ate the value itself — the whole point of the line — on cards under about 350px, and the figure is set in tabular numerals so it measures the same in Safari as in Chromium. Where one slot of a unit is calibrated and its neighbours are not, the neighbours hold the same row open so the fill bars stay level across the card.
 
 ### Fixed
+- **One handshake failure took out three queued jobs and every retry they had (#2898, reported by @grolmus)** — A print dispatch that met a TLS handshake failure spent its whole retry budget without opening a single socket. The cool-off that a failed handshake arms (#2780) lives inside `connect()`, so it applied to everything — including the dispatch, whose four attempts two seconds apart were all answered from the gate rather than the network. The reporter's farm logs the shape exactly: the delete that clears the way for the upload took the SSL error at 11:10:04.956, the upload's first attempt started 8ms later, and attempts two through four took one to two milliseconds each. Because the cool-off runs for five minutes, the next two jobs queued for that printer failed the same way inside the same window, and on that farm the failure is transient — a manual connect a second later completes cleanly — so the retry the gate suppressed is the one that would have worked. The gate was serving two callers that want opposite things from it. The background sweeps that fetch a 3MF, a cover or a timelapse after a print walk about a hundred and ten candidate paths against one wedged printer with nobody waiting, and backing off for minutes is right for them; they keep today's behaviour untouched. A dispatch is one delete plus at most four upload attempts with someone watching a progress bar, so it now ignores the cool-off, as does a firmware upload, for the same reason. Callers that do respect the cool-off no longer sleep out a retry loop against it either: the loop stops at the attempt that armed the gate and says so, instead of spending three more attempts and six seconds on connections that cannot happen. Two things that made this a log dive rather than a glance are fixed with it — the cool-off skip was the one connect failure that reported without naming its cause and did so at debug level, so four identical reason-free warnings were all the operator saw; it now says at warning level that nothing was sent and how long the printer has left, once per cool-off rather than once per attempt, so that raising it does not recreate the log flood #2780 set out to stop. And a dispatch that fails this way no longer tells anyone to check whether the SD card is inserted and formatted: nothing reached the printer's filesystem, so its card is the one part of the machine that was working, and the message now names the file service and rules the card out by name. That message is only used when a handshake failed during the dispatch itself, which is read from the cool-off moving rather than merely being armed — a background timelapse fetch for an earlier print can leave one armed for five minutes, and blaming TLS for an upload that really hit a full disk would be the same wrong-hardware mistake pointing the other way.
 - **Archived projects crowded out the live ones in every project picker (#2888, reported by @e77)** — The reporter files each job under its own project and archives it when the job is done, so five active projects sat behind thirty-odd finished ones in the Project dropdown of the Edit Archive dialog — an unscrolled list of everything ever created, with no way to tell which entries were still live. That dropdown, the one on the pending-uploads panel, the bulk "Add to Project" dialog and the File Manager's folder link now leave archived projects out. Completed projects stay: a project marked completed says the work is done, not that it should be hidden, and filing a reprint under one is ordinary. The Archives right-click submenu had gone the other way and offered active projects only, so a completed project was reachable from the Edit dialog and not from the menu beside it; all five surfaces now apply the same rule. Whatever an archive is already filed under stays on its own list whatever its status — a `<select>` holding a value none of its options match is reset by the browser to the first one, which here reads "No project", so an archive in an archived project would have stated that it was filed nowhere. The one picker deliberately left alone is the parent-project picker, where a finished or archived project is still a legal parent. Fixed alongside it: the status tabs on the Projects page counted only the projects the selected filter had already let through, so every tab but the current one counted zero and lost its badge entirely — the reporter's own screenshot shows "Active 5" beside a bare Completed and a bare Archived, with thirty projects behind them. They are counted from the whole fleet now. Covered by frontend tests.
 - **The full-page G-code preview grew without limit and never drew anything (#2887, reported by @ojimpo)** — Opening a 3D Preview from Archives left an empty white pane with the legend and layer slider floating over it, while the page's scrollbar shrank for as long as it stayed open — about 190px of page height per second, without stopping. Two faults compounded. The viewer appends its canvas into the very element it measures and watches for resizes, and three.js writes each new size onto the canvas as inline style, leaving it `display: inline` so the line box adds descender space on top; on a page where that element takes its height from its contents, the canvas was sizing the box that sizes the canvas, gaining a fixed 33px every round. And the page never gave it a height to take instead: the viewer pane is `flex-1 min-h-0`, which divides nothing unless the column above it is a definite height, and `h-full` is a percentage that resolves against a main area whose own height comes from a `min-height` — a floor, not a size — so it fell through to the content. Nothing was ever drawn because each observer callback reallocated and cleared the frame buffer before an antialiased render of what had grown to roughly 18 megapixels could finish. The canvas is now positioned out of flow, so it cannot contribute to the height of the element that measures it on any page, present or future, and that element takes a definite height from the pane around it rather than a percentage; the page itself is sized from the viewport the same way the File Manager page already was. The same viewer inside the File Manager dialog was never affected — a dialog gives it a fixed height, so neither fault could arise there. Nothing was wrong with the data path at any point: the legend and the layer slider were built from the parsed toolpath throughout, so the fetch, the parse and the layer split had all succeeded.
 - **A print could not start on the nozzle sitting in the H2C's rack (#2885, reported by @apizz)** — A job sliced for a 0.2mm nozzle failed in the queue with "install the matching nozzle before printing", even though a 0.2mm nozzle was in the tool-changer rack and the printer would have fetched it. Only picking the nozzle up by hand on the printer's own screen first let the print run, and because the item failed rather than waited, the rest of the queue went with it. The reporter noticed the giveaway: going *to* 0.4mm always worked, going *to* 0.2mm never did. The nozzle-diameter guard that catches a genuinely wrong slice before upload was measuring the wrong thing — it compared the sliced diameter against the two mounted hotends only, so on a machine whose hotends both read 0.4mm nothing but 0.4mm could ever pass, and the rack picker that would have fetched the right one runs further down the same dispatch and never got the chance. The rack now counts as reachable: a diameter parked in any dock satisfies the guard the same way a mounted one does. This was never only about 0.2mm — a 0.6mm slice was blocked identically. A diameter that is in neither a hotend nor a dock still stops the print before it uploads, and the message now lists both sets so it is clear what the machine actually has. Also fixed alongside it: an empty carriage keeps reporting the diameter of the nozzle it last held, so a hotend that had parked its nozzle back in the rack was counted as a mounted 0.4mm that was not there — presence is now read from the nozzle's own temperature rating and serial number, and a hotend is only discarded when both agree it is empty. Printers that report no rack at all are unaffected.
diff --git a/backend/app/api/routes/archives.py b/backend/app/api/routes/archives.py
index 3b87c7b53..4e1a07a21 100644
--- a/backend/app/api/routes/archives.py
+++ b/backend/app/api/routes/archives.py
@@ -2569,6 +2569,7 @@ async def scan_timelapse(
             max_retries=ftp_retry_count,
             retry_delay=ftp_retry_delay,
             operation_name=f"Download timelapse {matching_file['name']}",
+            cooloff_ip=printer.ip_address,
         )
     else:
         timelapse_data = await download_file_bytes_async(
@@ -2691,6 +2692,7 @@ async def select_timelapse(
             max_retries=ftp_retry_count,
             retry_delay=ftp_retry_delay,
             operation_name=f"Download timelapse {filename}",
+            cooloff_ip=printer.ip_address,
         )
     else:
         timelapse_data = await download_file_bytes_async(
diff --git a/backend/app/main.py b/backend/app/main.py
index c1ee84899..1a41ba0b7 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -3717,6 +3717,7 @@ async def on_print_start(printer_id: int, data: dict):
                             max_retries=ftp_retry_count,
                             retry_delay=ftp_retry_delay,
                             operation_name=f"Download 3MF from {remote_path}",
+                            cooloff_ip=printer.ip_address,
                             non_retry_exceptions=(FileNotOnPrinterError,),
                         )
                     else:
@@ -3796,6 +3797,7 @@ async def on_print_start(printer_id: int, data: dict):
                                     max_retries=ftp_retry_count,
                                     retry_delay=ftp_retry_delay,
                                     operation_name=f"Download 3MF from {remote_full_path}",
+                                    cooloff_ip=printer.ip_address,
                                 )
                             else:
                                 downloaded = await download_file_async(
@@ -3860,6 +3862,7 @@ async def on_print_start(printer_id: int, data: dict):
                                         max_retries=ftp_retry_count,
                                         retry_delay=ftp_retry_delay,
                                         operation_name=f"Re-download 3MF from {remote_path}",
+                                        cooloff_ip=printer.ip_address,
                                         non_retry_exceptions=(FileNotOnPrinterError,),
                                     )
                                 else:
diff --git a/backend/app/services/bambu_ftp.py b/backend/app/services/bambu_ftp.py
index 3d3bc86ec..d39ed3025 100644
--- a/backend/app/services/bambu_ftp.py
+++ b/backend/app/services/bambu_ftp.py
@@ -225,6 +225,10 @@ class BambuFTPClient:
     # their cool-off expires. See ``_HANDSHAKE_COOLOFF_SECONDS``.
     _handshake_blocked_until: dict[str, float] = {}
 
+    # Which cool-off deadline each printer's "not attempted" warning was last
+    # logged for, so the warning is said once per cool-off. See ``connect``.
+    _handshake_skip_logged: dict[str, float] = {}
+
     def __init__(
         self,
         ip_address: str,
@@ -232,12 +236,26 @@ class BambuFTPClient:
         timeout: float | None = None,
         printer_model: str | None = None,
         force_prot_c: bool = False,
+        respect_handshake_cooloff: bool = True,
     ):
+        """Set ``respect_handshake_cooloff=False`` for bounded, user-initiated work.
+
+        The cool-off exists to stop an unbounded sweep re-running one doomed
+        handshake a hundred times over (#2780). Dispatching a print is not
+        that: it is one delete plus at most four upload attempts, with someone
+        waiting on the result. Sharing the sweep's gate cost those attempts
+        their whole retry budget, and failed every further job queued for that
+        printer for the rest of the 300s window (#2898).
+
+        Leave it at the default everywhere else. Opting out is only defensible
+        because the caller's own connection count is bounded and small.
+        """
         self.ip_address = ip_address
         self.access_code = access_code
         self.timeout = timeout if timeout is not None else self.DEFAULT_TIMEOUT
         self.printer_model = printer_model
         self.force_prot_c = force_prot_c
+        self.respect_handshake_cooloff = respect_handshake_cooloff
         self._ftp: ImplicitFTP_TLS | None = None
 
     def _is_a1_model(self) -> bool:
@@ -283,6 +301,7 @@ class BambuFTPClient:
             # Drop it on the way past rather than leaving an entry per printer
             # this process has ever failed against.
             del cls._handshake_blocked_until[ip_address]
+            cls._handshake_skip_logged.pop(ip_address, None)
             return False
         return True
 
@@ -290,13 +309,35 @@ class BambuFTPClient:
         """Connect to the printer FTP server (implicit FTPS on port 990).
 
         Returns False without touching the network while the printer is inside
-        the cool-off a previous TLS handshake failure opened (#2780).
+        the cool-off a previous TLS handshake failure opened (#2780) -- unless
+        this client was built with ``respect_handshake_cooloff=False``.
         """
-        if self.handshake_blocked(self.ip_address):
-            logger.debug(
-                "FTP connect to %s skipped: FTPS handshake failed recently, cooling off",
-                self.ip_address,
-            )
+        if self.respect_handshake_cooloff and self.handshake_blocked(self.ip_address):
+            # WARNING, not DEBUG. This is the one connect() failure path that
+            # reported without its cause, so at default log level four
+            # reason-free "FTP connection failed" lines two seconds apart gave
+            # no hint that nothing had been sent (#2898). Every caller reaching
+            # here is already gated by handshake_blocked() at its own sweep
+            # boundary, so this costs about one line per print, not a flood.
+            deadline = self._handshake_blocked_until.get(self.ip_address)
+            remaining = max(0.0, deadline - time.monotonic()) if deadline is not None else 0.0
+            if deadline is not None and self._handshake_skip_logged.get(self.ip_address) != deadline:
+                self._handshake_skip_logged[self.ip_address] = deadline
+                logger.warning(
+                    "FTP connect to %s not attempted: its FTPS handshake failed recently and it is "
+                    "cooling off for another %.0fs. Nothing was sent to the printer.",
+                    self.ip_address,
+                    remaining,
+                )
+            else:
+                # Said once already for this cool-off. Repeating it per candidate
+                # path is the log flood #2780 set out to stop -- a download-zip
+                # of 200 files would print the same sentence 200 times.
+                logger.debug(
+                    "FTP connect to %s skipped: still cooling off for another %.0fs",
+                    self.ip_address,
+                    remaining,
+                )
             return False
         try:
             use_prot_c = self._should_use_prot_c()
@@ -928,6 +969,18 @@ class BambuFTPClient:
         return result if result else None
 
 
+def ftps_handshake_cooloff_deadline(ip_address: str) -> float | None:
+    """The monotonic deadline of this printer's handshake cool-off, or None.
+
+    Compare it across an operation to tell "a handshake failed while I was
+    working" from "this printer was already cooling off from something else".
+    Those need different words to the user, and the flag's presence alone
+    cannot separate them: a caller that opted out of the cool-off can be
+    running while an unrelated background fetch has one armed (#2898).
+    """
+    return BambuFTPClient._handshake_blocked_until.get(ip_address)
+
+
 def ftps_handshake_blocked(ip_address: str) -> bool:
     """True while this printer's FTPS handshake cool-off is still running.
 
@@ -1249,6 +1302,7 @@ async def upload_file_async(
     progress_callback: Callable[[int, int], None] | None = None,
     socket_timeout: float | None = None,
     printer_model: str | None = None,
+    respect_handshake_cooloff: bool = True,
 ) -> bool:
     """Async wrapper for uploading a file with timeout and progress callback.
 
@@ -1266,6 +1320,9 @@ async def upload_file_async(
         progress_callback: Optional callback for progress updates
         socket_timeout: FTP socket timeout for slow connections (e.g., A1 printers)
         printer_model: Printer model for A1-specific workarounds
+        respect_handshake_cooloff: see ``BambuFTPClient.__init__``. False for a
+            user-initiated upload, whose attempts are bounded and were being
+            spent against a cool-off that outlives them (#2898).
     """
     loop = asyncio.get_event_loop()
     is_a1 = printer_model in BambuFTPClient.A1_MODELS if printer_model else False
@@ -1287,7 +1344,12 @@ async def upload_file_async(
             f"mode={mode_str}, socket_timeout={socket_timeout}s, deadline={deadline:.0f}s)..."
         )
         client = BambuFTPClient(
-            ip_address, access_code, timeout=socket_timeout, printer_model=printer_model, force_prot_c=force_prot_c
+            ip_address,
+            access_code,
+            timeout=socket_timeout,
+            printer_model=printer_model,
+            force_prot_c=force_prot_c,
+            respect_handshake_cooloff=respect_handshake_cooloff,
         )
         if client.connect():
             logger.info("FTP connected to %s", ip_address)
@@ -1465,6 +1527,7 @@ async def delete_file_async(
     socket_timeout: float | None = None,
     printer_model: str | None = None,
     timeout: float = 60.0,
+    respect_handshake_cooloff: bool = True,
 ) -> DeleteResult:
     """Async wrapper for deleting a file.
 
@@ -1477,11 +1540,21 @@ async def delete_file_async(
         printer_model: Printer model for A1-specific workarounds
         timeout: overall async cap so a saturated ``_ftp_executor`` can't pin
             the caller (and any DB connection it holds) indefinitely (#2572).
+        respect_handshake_cooloff: see ``BambuFTPClient.__init__``. The delete
+            that clears the way for a dispatch shares the upload's exemption --
+            it is one connection, and in #2898's trace it is the one that armed
+            the cool-off the upload then spent all four attempts against.
     """
     loop = asyncio.get_event_loop()
 
     def _delete() -> DeleteResult:
-        client = BambuFTPClient(ip_address, access_code, timeout=socket_timeout, printer_model=printer_model)
+        client = BambuFTPClient(
+            ip_address,
+            access_code,
+            timeout=socket_timeout,
+            printer_model=printer_model,
+            respect_handshake_cooloff=respect_handshake_cooloff,
+        )
         if client.connect():
             try:
                 return client.delete_file(remote_path)
@@ -1710,6 +1783,7 @@ async def with_ftp_retry(
     retry_delay: float = 2.0,
     operation_name: str = "FTP operation",
     non_retry_exceptions: tuple[type[BaseException], ...] = (),
+    cooloff_ip: str | None = None,
     **kwargs,
 ) -> T | None:
     """Execute FTP operation with retry logic.
@@ -1721,6 +1795,10 @@ async def with_ftp_retry(
         retry_delay: Seconds to wait between retries (default: 2.0)
         operation_name: Name for logging purposes
         non_retry_exceptions: Exception types that should immediately abort retries
+        cooloff_ip: printer IP whose FTPS handshake cool-off should end the loop
+            early. Pass it from any caller that respects the cool-off; leave it
+            unset for one that opted out, or the loop would stop on a gate its
+            own attempts are ignoring (#2898).
         **kwargs: Keyword arguments for the operation
 
     Returns:
@@ -1731,8 +1809,10 @@ async def with_ftp_retry(
     another full deadline reaching the same conclusion (#2529).
     """
     last_error = None
+    attempts_made = 0
 
     for attempt in range(max_retries + 1):
+        attempts_made = attempt + 1
         try:
             result = await operation(*args, **kwargs)
             # Check for "falsy" success indicators
@@ -1753,10 +1833,28 @@ async def with_ftp_retry(
 
         # Don't wait after the last attempt
         if attempt < max_retries:
+            # A cool-off outlasts this loop by two orders of magnitude, so once
+            # it is armed every remaining attempt returns False without opening
+            # a socket. Spending them anyway bought nothing and cost the caller
+            # `max_retries * retry_delay` seconds of sleeping, then reported the
+            # failure with the wrong reason (#2898).
+            if cooloff_ip and ftps_handshake_blocked(cooloff_ip):
+                logger.warning(
+                    "%s: stopping after attempt %s/%s — %s is inside its FTPS handshake cool-off, "
+                    "so the remaining attempts would not reach it",
+                    operation_name,
+                    attempt + 1,
+                    max_retries + 1,
+                    cooloff_ip,
+                )
+                break
             logger.info("%s will retry in %ss...", operation_name, retry_delay)
             await asyncio.sleep(retry_delay)
 
-    logger.error("%s failed after %s attempts", operation_name, max_retries + 1)
+    # attempts_made, not max_retries + 1: the loop can stop early on a cool-off,
+    # and reporting attempts that were never made is how #2898 read as a network
+    # problem when nothing had gone near the network.
+    logger.error("%s failed after %s attempts", operation_name, attempts_made)
     if last_error:
         logger.debug("Last error: %s", last_error)
     return None
diff --git a/backend/app/services/firmware_update.py b/backend/app/services/firmware_update.py
index 55444c4d4..fdeea572c 100644
--- a/backend/app/services/firmware_update.py
+++ b/backend/app/services/firmware_update.py
@@ -344,6 +344,11 @@ class FirmwareUpdateService:
                     progress_callback=on_upload_progress,
                     socket_timeout=ftp_timeout,
                     printer_model=model,
+                    # Someone pressed "update firmware" and is watching a
+                    # progress bar. Bounded and user-initiated, like a print
+                    # dispatch, so it does not spend its retries on a cool-off
+                    # meant for the background sweeps (#2898).
+                    respect_handshake_cooloff=False,
                     max_retries=ftp_retry_count,
                     retry_delay=ftp_retry_delay,
                     operation_name=f"Upload firmware to printer {printer_id}",
@@ -357,6 +362,7 @@ class FirmwareUpdateService:
                     progress_callback=on_upload_progress,
                     socket_timeout=ftp_timeout,
                     printer_model=model,
+                    respect_handshake_cooloff=False,
                 )
 
             if not success:
diff --git a/backend/app/services/print_scheduler.py b/backend/app/services/print_scheduler.py
index 4501915d2..ac81a5113 100644
--- a/backend/app/services/print_scheduler.py
+++ b/backend/app/services/print_scheduler.py
@@ -33,6 +33,7 @@ from backend.app.services.bambu_ftp import (
     UploadCancelled,
     cache_3mf_download,
     delete_file_async,
+    ftps_handshake_cooloff_deadline,
     get_ftp_retry_settings,
     upload_file_async,
     with_ftp_retry,
@@ -6093,6 +6094,14 @@ class PrintScheduler:
         # pending->printing CAS) transparently open a fresh transaction.
         await db.commit()
 
+        # Where this printer's handshake cool-off stood before we touched it.
+        # The delete and upload below ignore the cool-off, so finding one armed
+        # afterwards proves nothing on its own -- a background timelapse or 3MF
+        # fetch for an earlier print could have armed it minutes ago. A deadline
+        # that MOVED, though, can only mean a handshake failed during this
+        # dispatch, which is what the failure message needs to know (#2898).
+        cooloff_before = ftps_handshake_cooloff_deadline(printer.ip_address)
+
         # Delete existing file if present (avoids 553 error on overwrite)
         try:
             logger.debug("Queue item %s: Deleting existing file %s if present...", item.id, remote_path)
@@ -6102,6 +6111,13 @@ class PrintScheduler:
                 remote_path,
                 socket_timeout=ftp_timeout,
                 printer_model=printer.model,
+                # This delete and the upload below are one bounded, user-initiated
+                # unit -- at most nine connections -- so neither skips on the
+                # handshake cool-off the opportunistic sweeps rely on. In #2898's
+                # trace this delete took the TLS failure and armed the cool-off,
+                # and the upload's four attempts were then spent against it
+                # without a socket being opened.
+                respect_handshake_cooloff=False,
             )
             logger.debug("Queue item %s: Delete result: %s", item.id, delete_result)
         except Exception as e:
@@ -6144,6 +6160,7 @@ class PrintScheduler:
                     socket_timeout=ftp_timeout,
                     printer_model=printer.model,
                     progress_callback=progress_bridge,
+                    respect_handshake_cooloff=False,
                     max_retries=ftp_retry_count,
                     retry_delay=ftp_retry_delay,
                     operation_name=f"Upload print to {printer.name}",
@@ -6157,6 +6174,7 @@ class PrintScheduler:
                     socket_timeout=ftp_timeout,
                     printer_model=printer.model,
                     progress_callback=progress_bridge,
+                    respect_handshake_cooloff=False,
                 )
         except UploadCancelled as e:
             uploaded = False
@@ -6174,6 +6192,20 @@ class PrintScheduler:
             injected_path.unlink(missing_ok=True)
 
         if not uploaded:
+            # A cool-off armed during this dispatch is proof the printer
+            # answered port 990 with something that was not TLS, so the SD card
+            # is the wrong thing to go and look at -- and it is what three of
+            # #2898's queue items were sent to check. "During this dispatch" is
+            # load-bearing: an unrelated background fetch can leave a cool-off
+            # armed for minutes, and blaming TLS for an upload that actually hit
+            # a full disk would repeat the mistake in the other direction.
+            cooloff_after = ftps_handshake_cooloff_deadline(printer.ip_address)
+            if not upload_error and cooloff_after is not None and cooloff_after != cooloff_before:
+                upload_error = (
+                    "The printer's file service did not answer over TLS, so the file could not be sent to it. "
+                    "Its SD card is not involved. Bambuddy will leave this printer alone for a few minutes "
+                    "before trying again."
+                )
             error_msg = upload_error or (
                 "Failed to upload file to printer. Check if SD card is inserted and properly formatted (FAT32/exFAT). "
                 "See server logs for detailed diagnostics."
diff --git a/backend/tests/unit/services/conftest.py b/backend/tests/unit/services/conftest.py
index 1191c35c9..38ed65438 100644
--- a/backend/tests/unit/services/conftest.py
+++ b/backend/tests/unit/services/conftest.py
@@ -127,9 +127,11 @@ def clear_ftp_mode_cache():
     """
     BambuFTPClient._mode_cache.clear()
     BambuFTPClient._handshake_blocked_until.clear()
+    BambuFTPClient._handshake_skip_logged.clear()
     yield
     BambuFTPClient._mode_cache.clear()
     BambuFTPClient._handshake_blocked_until.clear()
+    BambuFTPClient._handshake_skip_logged.clear()
 
 
 @pytest.fixture()
diff --git a/backend/tests/unit/services/test_ftp_cooloff_retry_budget_2898.py b/backend/tests/unit/services/test_ftp_cooloff_retry_budget_2898.py
new file mode 100644
index 000000000..a200dd059
--- /dev/null
+++ b/backend/tests/unit/services/test_ftp_cooloff_retry_budget_2898.py
@@ -0,0 +1,412 @@
+"""A dispatch must not spend its retries on a cool-off that outlives them (#2898).
+
+``BambuFTPClient.connect`` refuses to open a socket for 300s after a TLS
+handshake failure (#2780). That gate was written for the background sweeps --
+the post-print 3MF, cover and timelapse fetches, which walk ~110 candidate
+paths against one wedged printer and have nobody waiting on them.
+
+It sat inside ``connect``, so it applied to print dispatch too, which wants the
+opposite. On a 10-printer farm one handshake failure took out three queued
+jobs: the pre-upload delete armed the cool-off, all four upload attempts were
+then answered from the gate 2s apart without a socket being opened, and the
+next two jobs for that printer failed the same way inside the same window.
+
+The split these tests pin: work that is bounded and user-initiated (a dispatch
+is one delete plus at most four upload attempts) opts out; everything else
+keeps #2780's behaviour exactly. Sockets are counted rather than inferred,
+because "returned False" looks identical either way -- which is what made the
+original report a log dive.
+"""
+
+import logging
+import ssl
+from contextlib import ExitStack
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from backend.app.services import bambu_ftp
+from backend.app.services.bambu_ftp import (
+    BambuFTPClient,
+    DeleteResult,
+    delete_file_async,
+    upload_file_async,
+    with_ftp_retry,
+)
+
+pytestmark = pytest.mark.unit
+
+IP = "192.168.50.142"  # the P2S from the report
+LOGGER = "backend.app.services.bambu_ftp"
+
+
+@pytest.fixture(autouse=True)
+def _clean_cooloff():
+    BambuFTPClient._handshake_blocked_until.clear()
+    BambuFTPClient._handshake_skip_logged.clear()
+    BambuFTPClient._mode_cache.clear()
+    yield
+    BambuFTPClient._handshake_blocked_until.clear()
+    BambuFTPClient._handshake_skip_logged.clear()
+    BambuFTPClient._mode_cache.clear()
+
+
+@pytest.fixture()
+def refusing_printer():
+    """Answers port 990 with something that is not TLS, every time.
+
+    Yields the transport mock; ``transport.connect.call_count`` is the number
+    of times we actually went near the printer, which is the whole question
+    here.
+    """
+    transport = MagicMock()
+    transport.connect.side_effect = ssl.SSLError("[SSL: WRONG_VERSION_NUMBER] wrong version number")
+    with patch("backend.app.services.bambu_ftp.ImplicitFTP_TLS", return_value=transport):
+        yield transport
+
+
+def _arm(ip=IP):
+    """Put *ip* into the cool-off the way a real handshake failure would."""
+    BambuFTPClient._handshake_blocked_until[ip] = bambu_ftp.time.monotonic() + bambu_ftp._HANDSHAKE_COOLOFF_SECONDS
+    assert BambuFTPClient.handshake_blocked(ip) is True
+
+
+# ---------------------------------------------------------------------------
+# The gate itself
+# ---------------------------------------------------------------------------
+class TestConnectHonoursTheOptOut:
+    def test_the_default_still_refuses_to_open_a_socket(self, refusing_printer):
+        """#2780's protection is the default and must stay untouched."""
+        _arm()
+        assert BambuFTPClient(IP, "12345678", printer_model="P2S").connect() is False
+        assert refusing_printer.connect.call_count == 0
+
+    def test_an_exempt_client_reaches_the_printer(self, refusing_printer):
+        _arm()
+        client = BambuFTPClient(IP, "12345678", printer_model="P2S", respect_handshake_cooloff=False)
+        assert client.connect() is False  # the printer is still broken...
+        assert refusing_printer.connect.call_count == 1  # ...but we found that out ourselves
+
+    def test_the_opt_out_does_not_leak_to_the_next_client(self, refusing_printer):
+        """The flag is per client, not a global switch someone can leave on."""
+        _arm()
+        BambuFTPClient(IP, "12345678", respect_handshake_cooloff=False).connect()
+        refusing_printer.connect.reset_mock()
+
+        BambuFTPClient(IP, "12345678").connect()
+        assert refusing_printer.connect.call_count == 0
+
+    def test_the_skip_says_why_at_a_level_operators_see(self, caplog):
+        """The reason-free WARNING is what made this a log dive.
+
+        Every other ``connect`` failure path names its cause; this one logged
+        at DEBUG, so at default level four identical "FTP connection failed"
+        lines gave no hint that nothing had been sent.
+        """
+        _arm()
+        with caplog.at_level(logging.WARNING, logger=LOGGER):
+            assert BambuFTPClient(IP, "12345678").connect() is False
+
+        messages = [r.getMessage() for r in caplog.records]
+        assert any("cooling off" in m and IP in m for m in messages), messages
+        # And it has to be legible as "we did nothing", not as a network error.
+        assert any("Nothing was sent to the printer" in m for m in messages), messages
+
+    def test_it_says_it_once_per_cooloff_and_not_once_per_attempt(self, caplog):
+        """Raising this to WARNING must not re-create the flood #2780 stopped.
+
+        Not every caller is gated: downloading a ZIP of files the user picked
+        walks the whole selection, so 200 files would otherwise repeat the same
+        sentence 200 times.
+        """
+        _arm()
+        with caplog.at_level(logging.DEBUG, logger=LOGGER):
+            for _ in range(200):
+                BambuFTPClient(IP, "12345678").connect()
+
+        warnings = [r for r in caplog.records if r.levelno >= logging.WARNING]
+        assert len(warnings) == 1, [r.getMessage() for r in warnings]
+        # Still recoverable at DEBUG for anyone reading a support bundle.
+        assert sum("still cooling off" in r.getMessage() for r in caplog.records) == 199
+
+    def test_a_fresh_handshake_failure_is_announced_again(self, caplog):
+        """Once per cool-off, not once per process.
+
+        A printer that recovers and fails again is a new event, and silence
+        would be the DEBUG-level problem this fix set out to remove.
+        """
+        _arm()
+        with caplog.at_level(logging.WARNING, logger=LOGGER):
+            BambuFTPClient(IP, "12345678").connect()
+            _arm()  # a later handshake failure pushes the deadline out
+            BambuFTPClient(IP, "12345678").connect()
+
+        warnings = [r for r in caplog.records if r.levelno >= logging.WARNING]
+        assert len(warnings) == 2, [r.getMessage() for r in warnings]
+
+
+# ---------------------------------------------------------------------------
+# The retry loop
+# ---------------------------------------------------------------------------
+class TestRetryLoopStopsOnAnArmedCooloff:
+    async def _run(self, *, cooloff_ip, calls):
+        async def op():
+            calls.append(1)
+            _arm()  # the first attempt is what arms it, as in the report
+            return False
+
+        return await with_ftp_retry(
+            op,
+            max_retries=3,
+            retry_delay=0.01,
+            operation_name="Download 3MF",
+            cooloff_ip=cooloff_ip,
+        )
+
+    async def test_a_respecting_caller_stops_after_the_attempt_that_armed_it(self, caplog):
+        calls = []
+        with caplog.at_level(logging.WARNING, logger=LOGGER):
+            assert await self._run(cooloff_ip=IP, calls=calls) is None
+        assert len(calls) == 1
+
+        messages = [r.getMessage() for r in caplog.records]
+        assert any("stopping after attempt 1/4" in m for m in messages), messages
+        # The tally has to match what was really tried. "failed after 4
+        # attempts" for one attempt is how this read as a network problem.
+        assert any("failed after 1 attempts" in m for m in messages), messages
+
+    async def test_a_caller_without_the_ip_keeps_its_full_budget(self):
+        """Dispatch ignores the cool-off, so the loop must not stop on it.
+
+        Stopping here would undo the exemption from the other end: the
+        attempts would still be refused, just by the retry loop instead of by
+        ``connect``.
+        """
+        calls = []
+        assert await self._run(cooloff_ip=None, calls=calls) is None
+        assert len(calls) == 4
+
+
+# ---------------------------------------------------------------------------
+# The reported failure, end to end
+# ---------------------------------------------------------------------------
+class TestDispatchKeepsItsAttempts:
+    async def test_every_upload_attempt_reaches_the_printer(self, refusing_printer, tmp_path):
+        """The trace from the report: cool-off armed, then four dead attempts.
+
+        The reporter's evidence is that the handshake failure is transient --
+        a manual connect a second later completes cleanly -- so the retry the
+        gate suppressed is precisely the retry that would have worked.
+        """
+        _arm()
+        local = tmp_path / "job.gcode.3mf"
+        local.write_bytes(b"x" * 1024)
+
+        result = await with_ftp_retry(
+            upload_file_async,
+            IP,
+            "12345678",
+            local,
+            "/job.gcode.3mf",
+            timeout=5.0,
+            printer_model="P2S",
+            respect_handshake_cooloff=False,
+            max_retries=3,
+            retry_delay=0.01,
+            operation_name="Upload print to Bambulab P2S-4",
+        )
+
+        assert result is None
+        assert refusing_printer.connect.call_count == 4
+
+    async def test_without_the_exemption_the_same_upload_touches_nothing(self, refusing_printer, tmp_path):
+        """Mutation guard: revert the exemption and the test above must fail.
+
+        Without this, ``call_count == 4`` above would pass for the wrong reason
+        if the cool-off were ever simply removed.
+        """
+        _arm()
+        local = tmp_path / "job.gcode.3mf"
+        local.write_bytes(b"x" * 1024)
+
+        result = await with_ftp_retry(
+            upload_file_async,
+            IP,
+            "12345678",
+            local,
+            "/job.gcode.3mf",
+            timeout=5.0,
+            printer_model="P2S",
+            max_retries=3,
+            retry_delay=0.01,
+            operation_name="Upload print to Bambulab P2S-4",
+        )
+
+        assert result is None
+        assert refusing_printer.connect.call_count == 0
+
+    async def test_the_pre_upload_delete_is_exempt_too(self, refusing_printer):
+        """In the report's trace the delete is what armed the cool-off.
+
+        It runs 8ms before the upload's first attempt, so leaving it gated
+        would keep one whole dispatch's worth of the problem in place.
+        """
+        _arm()
+        result = await delete_file_async(
+            IP, "12345678", "/job.gcode.3mf", printer_model="P2S", respect_handshake_cooloff=False
+        )
+        assert result is DeleteResult.FAILED
+        assert refusing_printer.connect.call_count == 1
+
+    async def test_a_background_download_is_still_gated(self, refusing_printer):
+        """The sweeps keep #2780 exactly: nobody is waiting, so back off."""
+        _arm()
+        assert await bambu_ftp.download_file_bytes_async(IP, "12345678", "/timelapse/a.mp4") is None
+        assert refusing_printer.connect.call_count == 0
+
+
+# ---------------------------------------------------------------------------
+# What the operator is told
+# ---------------------------------------------------------------------------
+@pytest.fixture
+async def dispatch_case(tmp_path):
+    """Minimal one-printer, one-queued-job database for ``_start_print``."""
+    from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+
+    import backend.app.models  # noqa: F401 - populate Base.metadata
+    from backend.app.core.database import Base
+    from backend.app.models.archive import PrintArchive
+    from backend.app.models.print_queue import PrintQueueItem
+    from backend.app.models.printer import Printer
+
+    engine = create_async_engine("sqlite+aiosqlite:///:memory:", echo=False)
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+    session_maker = async_sessionmaker(engine, expire_on_commit=False)
+
+    base_dir = tmp_path / "case"
+    archive_rel = Path("archives") / "job.3mf"
+    archive_abs = base_dir / archive_rel
+    archive_abs.parent.mkdir(parents=True, exist_ok=True)
+    archive_abs.write_bytes(b"archive payload")
+
+    async with session_maker() as db:
+        printer = Printer(
+            name="Bambulab P2S-4",
+            serial_number="SERIAL",
+            ip_address=IP,
+            access_code="12345678",
+            model="P2S",
+        )
+        db.add(printer)
+        await db.flush()
+        archive = PrintArchive(
+            printer_id=printer.id,
+            filename="job.3mf",
+            file_path=str(archive_rel),
+            file_size=archive_abs.stat().st_size,
+            status="completed",
+        )
+        db.add(archive)
+        await db.flush()
+        item = PrintQueueItem(printer_id=printer.id, archive_id=archive.id, status="pending")
+        db.add(item)
+        await db.commit()
+        item_id = item.id
+
+    try:
+        yield SimpleNamespace(session_maker=session_maker, base_dir=base_dir, item_id=item_id)
+    finally:
+        await engine.dispose()
+
+
+async def _failed_dispatch_message(dispatch_case, *, handshake_fails: bool) -> str:
+    """Run one dispatch whose upload fails, and return what the user is told.
+
+    ``handshake_fails`` makes the stand-in upload arm the cool-off the way the
+    real one does when the printer answers port 990 with something other than
+    TLS -- which is the only thing that separates the two messages.
+    """
+    import backend.app.services.print_scheduler as scheduler_module
+    from backend.app.models.print_queue import PrintQueueItem
+    from backend.app.services.print_scheduler import PrintScheduler
+    from backend.tests._fixtures.background_tasks import discarding_spawn_patch
+
+    async def _upload(*_args, **_kwargs):
+        if handshake_fails:
+            _arm()
+        return False
+
+    scheduler = PrintScheduler()
+    async with dispatch_case.session_maker() as db:
+        item = await db.get(PrintQueueItem, dispatch_case.item_id)
+        patches = [
+            patch.object(scheduler_module.settings, "base_dir", dispatch_case.base_dir),
+            patch("backend.app.services.print_scheduler.printer_manager.is_connected", MagicMock(return_value=True)),
+            patch("backend.app.services.print_scheduler.printer_manager.get_status", MagicMock(return_value=None)),
+            patch(
+                "backend.app.services.print_scheduler.get_ftp_retry_settings",
+                AsyncMock(return_value=(False, 0, 0, 1.0)),
+            ),
+            patch("backend.app.services.print_scheduler.delete_file_async", AsyncMock(return_value=True)),
+            patch("backend.app.services.print_scheduler.upload_file_async", _upload),
+            patch("backend.app.services.print_scheduler.notification_service.on_queue_job_failed", AsyncMock()),
+            discarding_spawn_patch(),
+            patch.object(scheduler, "_propagate_owner_to_printer_manager", AsyncMock()),
+            patch.object(scheduler, "_power_off_if_needed", AsyncMock()),
+            patch.object(scheduler, "_preheat_and_soak", AsyncMock()),
+        ]
+        with ExitStack() as stack:
+            for p in patches:
+                stack.enter_context(p)
+            await scheduler._start_print(db, item)
+
+        refreshed = await db.get(PrintQueueItem, dispatch_case.item_id)
+        assert refreshed.status == "failed"
+        return refreshed.error_message or ""
+
+
+class TestTheFailureNamesTheRightHardware:
+    async def test_a_handshake_failure_does_not_send_anyone_to_the_sd_card(self, dispatch_case):
+        """Three of the report's queue items were told to check an SD card.
+
+        The printer had answered port 990 with something that was not TLS.
+        Nothing had reached its filesystem, so its card could not have been
+        the problem, and the operator was sent to look at the one part of the
+        machine that was working.
+        """
+        message = await _failed_dispatch_message(dispatch_case, handshake_fails=True)
+
+        assert "SD card is inserted" not in message, message
+        assert "did not answer over TLS" in message, message
+        # It goes further than dropping the advice: the card is the first thing
+        # anyone would reach for next, so the message rules it out by name.
+        assert "SD card is not involved" in message, message
+
+    async def test_an_ordinary_upload_failure_keeps_the_storage_advice(self, dispatch_case):
+        """No cool-off means no evidence about TLS, so the old wording stands.
+
+        This is the half that stops the new message from swallowing every
+        upload failure: the cool-off is read as evidence, not assumed.
+        """
+        assert BambuFTPClient.handshake_blocked(IP) is False
+        message = await _failed_dispatch_message(dispatch_case, handshake_fails=False)
+
+        assert "SD card is inserted" in message, message
+
+    async def test_a_cooloff_left_by_something_else_is_not_taken_as_evidence(self, dispatch_case):
+        """The printer can be cooling off from work this dispatch had no part in.
+
+        A background timelapse or 3MF fetch for an earlier print arms the same
+        gate, and it lasts five minutes. Since the dispatch ignores the gate, an
+        upload running underneath it can still fail on a full disk -- and
+        answering that with "the file service did not answer over TLS" would be
+        the same wrong-hardware mistake pointing the other way.
+        """
+        _arm()  # armed before the dispatch, and nothing re-arms it during
+        message = await _failed_dispatch_message(dispatch_case, handshake_fails=False)
+
+        assert "did not answer over TLS" not in message, message
+        assert "SD card is inserted" in message, message