diff --git a/src/operator/Synapse.Operator/Services/WorkflowInstanceController.cs b/src/operator/Synapse.Operator/Services/WorkflowInstanceController.cs
index 37c0ee1a..b4c28903 100644
--- a/src/operator/Synapse.Operator/Services/WorkflowInstanceController.cs
+++ b/src/operator/Synapse.Operator/Services/WorkflowInstanceController.cs
@@ -223,8 +223,15 @@ protected override async Task OnResourceDeletedAsync(WorkflowInstance workflowIn
     {
         ArgumentNullException.ThrowIfNull(workflowInstance);
         if (workflowInstance.Metadata.Labels != null && workflowInstance.Metadata.Labels.TryGetValue(SynapseDefaults.Resources.Labels.Operator, out var operatorQualifiedName)) return operatorQualifiedName == this.Operator.Resource.GetQualifiedName();
-        if (this.Workflows.TryGetValue(this.GetResourceCacheKey(workflowInstance.Spec.Definition.Name, workflowInstance.Spec.Definition.Namespace), out var workflow) && workflow != null
-            && workflow.Metadata.Labels != null && workflow.Metadata.Labels.TryGetValue(SynapseDefaults.Resources.Labels.Operator, out operatorQualifiedName)) return operatorQualifiedName == this.Operator.Resource.GetQualifiedName();
+        if (this.Workflows.TryGetValue(this.GetResourceCacheKey(workflowInstance.Spec.Definition.Name, workflowInstance.Spec.Definition.Namespace), out var workflow))
+        {
+            if (workflow.Metadata.Labels != null && workflow.Metadata.Labels.TryGetValue(SynapseDefaults.Resources.Labels.Operator, out operatorQualifiedName)) return operatorQualifiedName == this.Operator.Resource.GetQualifiedName();
+        }
+        else
+        {
+            // if we are not able to retrieve the workflow, we assume it has been ignored by selectors, and thus cannot be claimed
+            return false;
+        }
         return null;
     }