diff --git a/services/core/java/com/android/server/wm/LetterboxUiController.java b/services/core/java/com/android/server/wm/LetterboxUiController.java
index b8f01b8..1e7f8a5 100644
--- a/services/core/java/com/android/server/wm/LetterboxUiController.java
+++ b/services/core/java/com/android/server/wm/LetterboxUiController.java
@@ -918,12 +918,14 @@
     // Check if we are in the given pose and in fullscreen mode.
     // Note that we check the task rather than the parent as with ActivityEmbedding the parent might
     // be a TaskFragment, and its windowing mode is always MULTI_WINDOW, even if the task is
-    // actually fullscreen.
+    // actually fullscreen. If display is still in transition e.g. unfolding, don't return true
+    // for HALF_FOLDED state or app will flicker.
     private boolean isDisplayFullScreenAndInPosture(boolean isTabletop) {
         Task task = mActivityRecord.getTask();
         return mActivityRecord.mDisplayContent != null && task != null
                 && mActivityRecord.mDisplayContent.getDisplayRotation().isDeviceInPosture(
                         DeviceStateController.DeviceState.HALF_FOLDED, isTabletop)
+                && !mActivityRecord.mDisplayContent.inTransition()
                 && task.getWindowingMode() == WINDOWING_MODE_FULLSCREEN;
     }
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/SizeCompatTests.java b/services/tests/wmtests/src/com/android/server/wm/SizeCompatTests.java
index f2390c0..c3044cb 100644
--- a/services/tests/wmtests/src/com/android/server/wm/SizeCompatTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/SizeCompatTests.java
@@ -4520,6 +4520,35 @@
     }
 
     @Test
+    public void testUpdateResolvedBoundsVerticalPosition_unfoldDisplay_notTabletop() {
+        // Set up a display in portrait with a fixed-orientation LANDSCAPE app.
+        setUpDisplaySizeWithApp(1000, 2000);
+        mActivity.mDisplayContent.setIgnoreOrientationRequest(true /* ignoreOrientationRequest */);
+        mActivity.mWmService.mLetterboxConfiguration.setLetterboxVerticalPositionMultiplier(
+                1.0f /*letterboxVerticalPositionMultiplier*/);
+        prepareUnresizable(mActivity, SCREEN_ORIENTATION_LANDSCAPE);
+
+        // Make the activity full-screen.
+        mTask.setWindowingMode(WINDOWING_MODE_FULLSCREEN);
+
+        // Simulate display unfolding.
+        setFoldablePosture(true /* isHalfFolded */, true /* isTabletop */);
+        doReturn(true).when(mActivity.mDisplayContent).inTransition();
+        resizeDisplay(mTask.mDisplayContent, 1400, 2800);
+
+        // Make sure app doesn't jump to top (default tabletop position) when unfolding.
+        assertEquals(1.0f, mActivity.mLetterboxUiController.getVerticalPositionMultiplier(
+                mActivity.getParent().getConfiguration()), 0);
+
+        // Simulate display fully open after unfolding.
+        setFoldablePosture(false /* isHalfFolded */, false /* isTabletop */);
+        doReturn(false).when(mActivity.mDisplayContent).inTransition();
+
+        assertEquals(1.0f, mActivity.mLetterboxUiController.getVerticalPositionMultiplier(
+                mActivity.getParent().getConfiguration()), 0);
+    }
+
+    @Test
     public void testGetFixedOrientationLetterboxAspectRatio_tabletop_centered() {
         // Set up a display in portrait with a fixed-orientation LANDSCAPE app
         setUpDisplaySizeWithApp(1400, 2800);