diff --git a/awx/main/scheduler/task_manager.py b/awx/main/scheduler/task_manager.py
index 943d4960e6..810fbafdac 100644
--- a/awx/main/scheduler/task_manager.py
+++ b/awx/main/scheduler/task_manager.py
@@ -234,9 +234,11 @@ class TaskManager():
     def get_dependent_jobs_for_inv_and_proj_update(self, job_obj):
         return [{'type': j.model_to_str(), 'id': j.id} for j in job_obj.dependent_jobs.all()]
 
-    def start_task(self, task, rampart_group, dependent_tasks=[]):
+    def start_task(self, task, rampart_group, dependent_tasks=None):
         from awx.main.tasks import handle_work_error, handle_work_success
 
+        dependent_tasks = dependent_tasks or []
+
         task_actual = {
             'type': get_type_for_model(type(task)),
             'id': task.id,