diff --git a/services/core/java/com/android/server/wm/RecentTasks.java b/services/core/java/com/android/server/wm/RecentTasks.java
index 9ef5ed051a13e..4faaf5170f277 100644
--- a/services/core/java/com/android/server/wm/RecentTasks.java
+++ b/services/core/java/com/android/server/wm/RecentTasks.java
@@ -682,6 +682,26 @@ class RecentTasks {
         }
     }
 
+    /**
+     * Removes the oldest recent task that is compatible with the given one. This is possible if
+     * the task windowing mode changed after being added to the Recents.
+     */
+    void removeCompatibleRecentTask(Task task) {
+        final int taskIndex = mTasks.indexOf(task);
+        if (taskIndex < 0) {
+            return;
+        }
+
+        final int candidateIndex = findRemoveIndexForTask(task, false /* includingSelf */);
+        if (candidateIndex == -1) {
+            // Nothing to trim
+            return;
+        }
+
+        final Task taskToRemove = taskIndex > candidateIndex ? task : mTasks.get(candidateIndex);
+        remove(taskToRemove);
+    }
+
     void removeTasksByPackageName(String packageName, int userId) {
         for (int i = mTasks.size() - 1; i >= 0; --i) {
             final Task task = mTasks.get(i);
@@ -1540,6 +1560,10 @@ class RecentTasks {
      * list (if any).
      */
     private int findRemoveIndexForAddTask(Task task) {
+        return findRemoveIndexForTask(task, true /* includingSelf */);
+    }
+
+    private int findRemoveIndexForTask(Task task, boolean includingSelf) {
         final int recentsCount = mTasks.size();
         final Intent intent = task.intent;
         final boolean document = intent != null && intent.isDocument();
@@ -1595,6 +1619,8 @@ class RecentTasks {
                     // existing task
                     continue;
                 }
+            } else if (!includingSelf) {
+                continue;
             }
             return i;
         }
diff --git a/services/core/java/com/android/server/wm/WindowOrganizerController.java b/services/core/java/com/android/server/wm/WindowOrganizerController.java
index 541fa9413f45e..5d239eb993afe 100644
--- a/services/core/java/com/android/server/wm/WindowOrganizerController.java
+++ b/services/core/java/com/android/server/wm/WindowOrganizerController.java
@@ -1615,6 +1615,7 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
         final int count = tasksToReparent.size();
         for (int i = 0; i < count; ++i) {
             final Task task = tasksToReparent.get(i);
+            final int prevWindowingMode = task.getWindowingMode();
             if (syncId >= 0) {
                 addToSyncSet(syncId, task);
             }
@@ -1628,6 +1629,12 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
                         hop.getToTop() ? POSITION_TOP : POSITION_BOTTOM,
                         false /*moveParents*/, "processChildrenTaskReparentHierarchyOp");
             }
+            // Trim the compatible Recent task (if any) after the Task is reparented and now has
+            // a different windowing mode, in order to prevent redundant Recent tasks after
+            // reparenting.
+            if (prevWindowingMode != task.getWindowingMode()) {
+                mService.mTaskSupervisor.mRecentTasks.removeCompatibleRecentTask(task);
+            }
         }
 
         if (transition != null) transition.collect(newParent);
diff --git a/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java b/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
index b02b774da86ae..df0808f72c3f2 100644
--- a/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
@@ -1315,6 +1315,26 @@ public class RecentTasksTest extends WindowTestsBase {
         assertTrue(info.supportsMultiWindow);
     }
 
+    @Test
+    public void testRemoveCompatibleRecentTask() {
+        final Task task1 = createTaskBuilder(".Task").setWindowingMode(
+                WINDOWING_MODE_FULLSCREEN).build();
+        mRecentTasks.add(task1);
+        final Task task2 = createTaskBuilder(".Task").setWindowingMode(
+                WINDOWING_MODE_MULTI_WINDOW).build();
+        mRecentTasks.add(task2);
+        assertEquals(2, mRecentTasks.getRecentTasks(MAX_VALUE, 0 /* flags */,
+                true /* getTasksAllowed */, TEST_USER_0_ID, 0).getList().size());
+
+        // Set windowing mode and ensure the same fullscreen task that created earlier is removed.
+        task2.setWindowingMode(WINDOWING_MODE_FULLSCREEN);
+        mRecentTasks.removeCompatibleRecentTask(task2);
+        assertEquals(1, mRecentTasks.getRecentTasks(MAX_VALUE, 0 /* flags */,
+                true /* getTasksAllowed */, TEST_USER_0_ID, 0).getList().size());
+        assertEquals(task2.mTaskId, mRecentTasks.getRecentTasks(MAX_VALUE, 0 /* flags */,
+                true /* getTasksAllowed */, TEST_USER_0_ID, 0).getList().get(0).taskId);
+    }
+
     private TaskSnapshot createSnapshot(Point taskSize, Point bufferSize) {
         HardwareBuffer buffer = null;
         if (bufferSize != null) {