diff --git a/amoro-ams/src/main/java/org/apache/amoro/server/optimizing/OptimizingQueue.java b/amoro-ams/src/main/java/org/apache/amoro/server/optimizing/OptimizingQueue.java
index 178bebaa39..2627078b59 100644
--- a/amoro-ams/src/main/java/org/apache/amoro/server/optimizing/OptimizingQueue.java
+++ b/amoro-ams/src/main/java/org/apache/amoro/server/optimizing/OptimizingQueue.java
@@ -775,7 +775,10 @@ private void resetTask(TaskRuntime<RewriteStageTask> taskRuntime) {
 
     @Override
     public boolean isClosed() {
-      return status == ProcessStatus.KILLED;
+      // close() sets CLOSED (KILLED is reserved for kill flows); checking only KILLED made
+      // this predicate permanently false, so the acceptResult guard against late results on a
+      // closed process could never fire.
+      return status == ProcessStatus.CLOSED || status == ProcessStatus.KILLED;
     }
 
     @Override
diff --git a/amoro-ams/src/test/java/org/apache/amoro/server/optimizing/TestOptimizingQueue.java b/amoro-ams/src/test/java/org/apache/amoro/server/optimizing/TestOptimizingQueue.java
index 3955e335e3..37e2c63000 100644
--- a/amoro-ams/src/test/java/org/apache/amoro/server/optimizing/TestOptimizingQueue.java
+++ b/amoro-ams/src/test/java/org/apache/amoro/server/optimizing/TestOptimizingQueue.java
@@ -858,6 +858,8 @@ public void testProcessCloseKeepsLastOptimizedSnapshotId() {
     // Close process without success (simulates group change / forced termination)
     process.close(false);
 
+    Assert.assertTrue(process.isClosed());
+
     // lastOptimizedSnapshotId and lastOptimizedChangeSnapshotId should NOT be updated
     Assert.assertEquals(snapshotIdBeforePlanning, tableRuntime.getLastOptimizedSnapshotId());
     Assert.assertEquals(