diff --git a/services/core/java/com/android/server/wm/Transition.java b/services/core/java/com/android/server/wm/Transition.java
index 155db2c586542..d86382d1858f4 100644
--- a/services/core/java/com/android/server/wm/Transition.java
+++ b/services/core/java/com/android/server/wm/Transition.java
@@ -1328,7 +1328,7 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
     }
 
     boolean getLegacyIsReady() {
-        return mState == STATE_STARTED && mSyncId >= 0 && mSyncEngine.isReady(mSyncId);
+        return (mState == STATE_STARTED || mState == STATE_COLLECTING) && mSyncId >= 0;
     }
 
     static Transition fromBinder(IBinder binder) {
diff --git a/services/core/java/com/android/server/wm/TransitionController.java b/services/core/java/com/android/server/wm/TransitionController.java
index 7a031db3a226f..60307ce220007 100644
--- a/services/core/java/com/android/server/wm/TransitionController.java
+++ b/services/core/java/com/android/server/wm/TransitionController.java
@@ -94,6 +94,9 @@ class TransitionController {
     // TODO(b/188595497): remove when not needed.
     final StatusBarManagerInternal mStatusBar;
 
+    /** Pending transitions from Shell that are waiting the SyncEngine to be free. */
+    private final ArrayList<PendingStartTransition> mPendingTransitions = new ArrayList<>();
+
     TransitionController(ActivityTaskManagerService atm,
             TaskSnapshotController taskSnapshotController) {
         mAtm = atm;
@@ -160,9 +163,11 @@ class TransitionController {
         }
         final PendingStartTransition out = new PendingStartTransition(new Transition(type,
                 0 /* flags */, this, mAtm.mWindowManager.mSyncEngine));
+        mPendingTransitions.add(out);
         // We want to start collecting immediately when the engine is free, otherwise it may
         // be busy again.
         out.setStartSync(() -> {
+            mPendingTransitions.remove(out);
             moveToCollecting(out.mTransition);
         });
         ProtoLog.v(ProtoLogGroup.WM_DEBUG_WINDOW_TRANSITIONS, "Creating PendingTransition: %s",
@@ -530,7 +535,10 @@ class TransitionController {
         int state = LEGACY_STATE_IDLE;
         if (!mPlayingTransitions.isEmpty()) {
             state = LEGACY_STATE_RUNNING;
-        } else if (mCollectingTransition != null && mCollectingTransition.getLegacyIsReady()) {
+        } else if ((mCollectingTransition != null && mCollectingTransition.getLegacyIsReady())
+                || !mPendingTransitions.isEmpty()) {
+            // The transition may not be "ready", but we have transition waiting to start, so it
+            // can't be IDLE for test purpose. Ideally, we should have a STATE_COLLECTING.
             state = LEGACY_STATE_READY;
         }
         proto.write(AppTransitionProto.APP_TRANSITION_STATE, state);