diff --git a/api/core/app/apps/base_app_queue_manager.py b/api/core/app/apps/base_app_queue_manager.py
index 698eee9894..b41bedbea4 100644
--- a/api/core/app/apps/base_app_queue_manager.py
+++ b/api/core/app/apps/base_app_queue_manager.py
@@ -90,6 +90,7 @@ class AppQueueManager:
         """
         self._clear_task_belong_cache()
         self._q.put(None)
+        self._graph_runtime_state = None  # Release reference to allow GC to reclaim memory
 
     def _clear_task_belong_cache(self) -> None:
         """