diff --git a/Tests/Acceptance/DoctrineClientManagerTest.php b/Tests/Acceptance/DoctrineClientManagerTest.php
index c6d181fe..0d3866c7 100644
--- a/Tests/Acceptance/DoctrineClientManagerTest.php
+++ b/Tests/Acceptance/DoctrineClientManagerTest.php
@@ -113,6 +113,8 @@ public function testClientDeleteCascadesToAccessTokensAndRefreshTokens(): void
                 )
         );
 
+        // The entity manager has to be cleared manually
+        // because it doesn't process deep integrity constraints
         $em->clear();
 
         /** @var $refreshToken RefreshToken */