diff --git a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
index f9524768dff..b3d7d521e14 100644
--- a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
@@ -930,10 +930,20 @@ public class IndexWriter implements Closeable, TwoPhaseCommit{
           closeInternal(waitForMerges, true);
         }
       }
-      assert eventQueue.isEmpty();
+      assert assertEventQueueAfterClose();
     }
   }
 
+  private boolean assertEventQueueAfterClose() {
+    if (eventQueue.isEmpty()) {
+      return true;
+    }
+    for (Event e : eventQueue) {
+      assert e instanceof DocumentsWriter.MergePendingEvent : e;
+    }
+    return true;
+  }
+
   // Returns true if this thread should attempt to close, or
   // false if IndexWriter is now closed; else, waits until
   // another thread finishes closing
@@ -2022,7 +2032,7 @@ public class IndexWriter implements Closeable, TwoPhaseCommit{
         rollbackInternal();
       }
     }
-    assert eventQueue.isEmpty() : eventQueue;
+    assert assertEventQueueAfterClose();
   }
 
   private void rollbackInternal() throws IOException {