diff --git a/xpcom/threads/TaskQueue.cpp b/xpcom/threads/TaskQueue.cpp
index 0e8e5fba3694..0af4813e1f42 100644
--- a/xpcom/threads/TaskQueue.cpp
+++ b/xpcom/threads/TaskQueue.cpp
@@ -108,10 +108,8 @@ void TaskQueue::AwaitShutdownAndIdle() {
 }
 
 void TaskQueue::OnDelayedRunnableCreated(DelayedRunnable* aRunnable) {
-#ifdef DEBUG
   MonitorAutoLock mon(mQueueMonitor);
-  MOZ_ASSERT(!mDelayedRunnablesCancelPromise);
-#endif
+  MOZ_RELEASE_ASSERT(!mDelayedRunnablesCancelPromise);
 }
 
 void TaskQueue::OnDelayedRunnableScheduled(DelayedRunnable* aRunnable) {