diff --git a/services/core/java/com/android/server/wm/RecentTasks.java b/services/core/java/com/android/server/wm/RecentTasks.java
index 6631a3e61e77d..e357572667d5c 100644
--- a/services/core/java/com/android/server/wm/RecentTasks.java
+++ b/services/core/java/com/android/server/wm/RecentTasks.java
@@ -1433,20 +1433,18 @@ class RecentTasks {
 
     /** @return whether the given task can be trimmed even if it is outside the visible range. */
     protected boolean isTrimmable(Task task) {
-        final Task rootTask = task.getRootTask();
-
-        // No stack for task, just trim it
-        if (rootTask == null) {
+        // The task was detached, just trim it.
+        if (!task.isAttached()) {
             return true;
         }
 
         // Ignore tasks from different displays
         // TODO (b/115289124): No Recents on non-default displays.
-        if (!rootTask.isOnHomeDisplay()) {
+        if (!task.isOnHomeDisplay()) {
             return false;
         }
 
-        final Task rootHomeTask = rootTask.getDisplayArea().getRootHomeTask();
+        final Task rootHomeTask = task.getDisplayArea().getRootHomeTask();
         // Home task does not exist. Don't trim the task.
         if (rootHomeTask == null) {
             return false;
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 5d6a5c0b51677..73404eb6f0fd9 100644
--- a/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/RecentTasksTest.java
@@ -641,7 +641,6 @@ public class RecentTasksTest extends WindowTestsBase {
 
     @Test
     public void testVisibleTasks_excludedFromRecents() {
-        mRecentTasks.setOnlyTestVisibleRange();
         mRecentTasks.setParameters(-1 /* min */, 4 /* max */, -1 /* ms */);
 
         Task excludedTask1 = createTaskBuilder(".ExcludedTask1")
@@ -650,15 +649,26 @@ public class RecentTasksTest extends WindowTestsBase {
         Task excludedTask2 = createTaskBuilder(".ExcludedTask2")
                 .setFlags(FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS)
                 .build();
+        Task detachedExcludedTask = createTaskBuilder(".DetachedExcludedTask")
+                .setFlags(FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS)
+                .build();
 
+        // Move home to front so other task can satisfy the condition in RecentTasks#isTrimmable.
+        mRootWindowContainer.getDefaultTaskDisplayArea().getRootHomeTask().moveToFront("test");
+        // Avoid Task#autoRemoveFromRecents when removing from parent.
+        detachedExcludedTask.setHasBeenVisible(true);
+        detachedExcludedTask.removeImmediately();
+        assertFalse(detachedExcludedTask.isAttached());
+
+        mRecentTasks.add(detachedExcludedTask);
         mRecentTasks.add(excludedTask1);
         mRecentTasks.add(mTasks.get(0));
         mRecentTasks.add(mTasks.get(1));
         mRecentTasks.add(mTasks.get(2));
         mRecentTasks.add(excludedTask2);
 
-        // The last excluded task should be trimmed, while the first-most excluded task should not
-        triggerTrimAndAssertTrimmed(excludedTask1);
+        // Except the first-most excluded task, other excluded tasks should be trimmed.
+        triggerTrimAndAssertTrimmed(excludedTask1, detachedExcludedTask);
     }
 
     @Test