diff --git a/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/LedgerHandle.java b/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/LedgerHandle.java
index 04270c72f53..ea5295dc7a8 100644
--- a/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/LedgerHandle.java
+++ b/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/LedgerHandle.java
@@ -1870,7 +1870,8 @@ void handleBookieFailure(final Map<Integer, BookieId> failedBookies) {
                 LOG.debug("Ensemble change is disabled. Retry sending to failed bookies {} for ledger {}.",
                     failedBookies, ledgerId);
             }
-            unsetSuccessAndSendWriteRequest(getCurrentEnsemble(), failedBookies.keySet());
+            executeOrdered(() ->
+                    unsetSuccessAndSendWriteRequest(getCurrentEnsemble(), failedBookies.keySet()));
             return;
         }
 
diff --git a/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/PendingAddOp.java b/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/PendingAddOp.java
index 8dc50370194..3a78696e886 100644
--- a/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/PendingAddOp.java
+++ b/bookkeeper-server/src/main/java/org/apache/bookkeeper/client/PendingAddOp.java
@@ -231,7 +231,7 @@ synchronized void unsetSuccessAndSendWriteRequest(List<BookieId> ensemble, int b
     /**
      * Initiate the add operation.
      */
-    public void initiate() {
+    public synchronized void initiate() {
         hasRun = true;
         if (callbackTriggered) {
             // this should only be true if the request was failed due
@@ -452,7 +452,7 @@ private PendingAddOp(Handle<PendingAddOp> recyclerHandle) {
     }
 
 
-    private void maybeRecycle() {
+    private synchronized void maybeRecycle() {
         /**
          * We have opportunity to recycle two objects here.
          * PendingAddOp#toSend and LedgerHandle#pendingAddOp
@@ -482,7 +482,7 @@ private void maybeRecycle() {
         }
     }
 
-    public void recyclePendAddOpObject() {
+    public synchronized void recyclePendAddOpObject() {
         entryId = LedgerHandle.INVALID_ENTRY_ID;
         currentLedgerLength = -1;
         if (payload != null) {