diff --git a/src/Symfony/Component/Lock/Store/PostgreSqlStore.php b/src/Symfony/Component/Lock/Store/PostgreSqlStore.php
index fbf0aa071d..9fdbe94bac 100644
--- a/src/Symfony/Component/Lock/Store/PostgreSqlStore.php
+++ b/src/Symfony/Component/Lock/Store/PostgreSqlStore.php
@@ -87,6 +87,7 @@ class PostgreSqlStore implements BlockingSharedLockStoreInterface, BlockingStore
 
         // Check if lock is acquired
         if (true === (\is_object($result) ? $result->fetchOne() : $stmt->fetchColumn())) {
+            $key->markUnserializable();
             // release sharedLock in case of promotion
             $this->unlockShared($key);
 
@@ -109,6 +110,7 @@ class PostgreSqlStore implements BlockingSharedLockStoreInterface, BlockingStore
 
         // Check if lock is acquired
         if (true === (\is_object($result) ? $result->fetchOne() : $stmt->fetchColumn())) {
+            $key->markUnserializable();
             // release lock in case of demotion
             $this->unlock($key);