diff --git a/src/Normalizer/RelationshipItemNormalizer.php b/src/Normalizer/RelationshipItemNormalizer.php
index f2ca5d2..07923e8 100644
--- a/src/Normalizer/RelationshipItemNormalizer.php
+++ b/src/Normalizer/RelationshipItemNormalizer.php
@@ -125,7 +125,7 @@ class RelationshipItemNormalizer extends FieldItemNormalizer implements UuidRefe
    * {@inheritdoc}
    */
   public function getUuid($data) {
-    if (isset($data['uuid'])) {
+    if (empty($data['uuid'])) {
       return NULL;
     }
     $uuid = $data['uuid'];