diff --git a/services/core/java/com/android/server/wm/RootWindowContainer.java b/services/core/java/com/android/server/wm/RootWindowContainer.java
index d9a954f..05f95f81 100644
--- a/services/core/java/com/android/server/wm/RootWindowContainer.java
+++ b/services/core/java/com/android/server/wm/RootWindowContainer.java
@@ -3212,6 +3212,10 @@
                         + "not idle", rootTask.getRootTaskId(), resumedActivity);
                 return false;
             }
+            if (mTransitionController.isTransientLaunch(resumedActivity)) {
+                // Not idle if the transient transition animation is running.
+                return false;
+            }
         }
         // End power mode launch when idle.
         mService.endLaunchPowerMode(ActivityTaskManagerService.POWER_MODE_REASON_START_ACTIVITY);
diff --git a/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java b/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
index ed0c8ef..d4fabf4 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
@@ -61,6 +61,7 @@
 import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
@@ -1425,6 +1426,15 @@
         // No need to wait for the activity in transient hide task.
         assertEquals(WindowContainer.SYNC_STATE_NONE, activity1.mSyncState);
 
+        // An active transient launch overrides idle state to avoid clearing power mode before the
+        // transition is finished.
+        spyOn(mRootWindowContainer.mTransitionController);
+        doAnswer(invocation -> controller.isTransientLaunch(invocation.getArgument(0))).when(
+                mRootWindowContainer.mTransitionController).isTransientLaunch(any());
+        activity2.getTask().setResumedActivity(activity2, "test");
+        activity2.idle = true;
+        assertFalse(mRootWindowContainer.allResumedActivitiesIdle());
+
         activity1.setVisibleRequested(false);
         activity2.setVisibleRequested(true);
         activity2.setVisible(true);