diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index ed6a65e3e4b..200da1f1222 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -2812,10 +2812,6 @@ public function createEntity($className, array $data, &$hints = [])
                         $joinColumnValue = $data[$srcColumn] ?? null;
 
                         if ($joinColumnValue !== null) {
-                            if ($joinColumnValue instanceof BackedEnum) {
-                                $joinColumnValue = $joinColumnValue->value;
-                            }
-
                             if ($targetClass->containsForeignIdentifier) {
                                 $associatedId[$targetClass->getFieldForColumn($targetColumn)] = $joinColumnValue;
                             } else {
@@ -2847,7 +2843,8 @@ public function createEntity($className, array $data, &$hints = [])
                     // Check identity map first
                     // FIXME: Can break easily with composite keys if join column values are in
                     //        wrong order. The correct order is the one in ClassMetadata#identifier.
-                    $relatedIdHash = implode(' ', $associatedId);
+                    $associatedIdFlattened = $this->identifierFlattener->flattenIdentifier($targetClass, $associatedId);
+                    $relatedIdHash         = implode(' ', $associatedIdFlattened);
 
                     switch (true) {
                         case isset($this->identityMap[$targetClass->rootEntityName][$relatedIdHash]):