diff --git a/api/v1alpha1/horizontalrunnerautoscaler_types.go b/api/v1alpha1/horizontalrunnerautoscaler_types.go
index f1e1d78e..2bf5cb66 100644
--- a/api/v1alpha1/horizontalrunnerautoscaler_types.go
+++ b/api/v1alpha1/horizontalrunnerautoscaler_types.go
@@ -156,6 +156,7 @@ type HorizontalRunnerAutoscalerStatus struct {
 	DesiredReplicas *int `json:"desiredReplicas,omitempty"`
 
 	// +optional
+	// +nullable
 	LastSuccessfulScaleOutTime *metav1.Time `json:"lastSuccessfulScaleOutTime,omitempty"`
 
 	// +optional
diff --git a/charts/actions-runner-controller/Chart.yaml b/charts/actions-runner-controller/Chart.yaml
index 75100f06..b68e248b 100644
--- a/charts/actions-runner-controller/Chart.yaml
+++ b/charts/actions-runner-controller/Chart.yaml
@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.10.1
+version: 0.10.2
 
 home: https://github.com/summerwind/actions-runner-controller
 
diff --git a/charts/actions-runner-controller/crds/actions.summerwind.dev_horizontalrunnerautoscalers.yaml b/charts/actions-runner-controller/crds/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
index 7c261b3f..b7cd99ae 100644
--- a/charts/actions-runner-controller/crds/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
+++ b/charts/actions-runner-controller/crds/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
@@ -207,6 +207,7 @@ spec:
               type: integer
             lastSuccessfulScaleOutTime:
               format: date-time
+              nullable: true
               type: string
             observedGeneration:
               description: ObservedGeneration is the most recent generation observed
diff --git a/config/crd/bases/actions.summerwind.dev_horizontalrunnerautoscalers.yaml b/config/crd/bases/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
index 7c261b3f..b7cd99ae 100644
--- a/config/crd/bases/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
+++ b/config/crd/bases/actions.summerwind.dev_horizontalrunnerautoscalers.yaml
@@ -207,6 +207,7 @@ spec:
               type: integer
             lastSuccessfulScaleOutTime:
               format: date-time
+              nullable: true
               type: string
             observedGeneration:
               description: ObservedGeneration is the most recent generation observed