diff --git a/google-cloud-firestore/src/main/java/com/google/cloud/firestore/BulkWriter.java b/google-cloud-firestore/src/main/java/com/google/cloud/firestore/BulkWriter.java
index 8e104ed7a..bb9d75090 100644
--- a/google-cloud-firestore/src/main/java/com/google/cloud/firestore/BulkWriter.java
+++ b/google-cloud-firestore/src/main/java/com/google/cloud/firestore/BulkWriter.java
@@ -988,8 +988,10 @@ private void sendBatchLocked(final BulkCommitBatch batch, final boolean flush) {
               new Runnable() {
                 @Override
                 public void run() {
-                  synchronized (lock) {
-                    scheduleCurrentBatchLocked(flush);
+                  if (flush) {
+                    synchronized (lock) {
+                      scheduleCurrentBatchLocked(/* flush= */ true);
+                    }
                   }
                 }
               },