diff --git a/src/EntityClone/Content/ContentEntityCloneFormBase.php b/src/EntityClone/Content/ContentEntityCloneFormBase.php
index 3e402a8..40f62ad 100644
--- a/src/EntityClone/Content/ContentEntityCloneFormBase.php
+++ b/src/EntityClone/Content/ContentEntityCloneFormBase.php
@@ -153,7 +153,9 @@ protected function getRecursiveFormElement(FieldConfigInterface $field_definitio
         '#type' => 'hidden',
         '#value' => $referenced_entity->bundle(),
       ];
-      $form_element[$field_definition->id()]['references'][$referenced_entity->id()]['children'] = $this->getChildren($referenced_entity);
+      if ($referenced_entity instanceOf ContentEntityInterface) {
+        $form_element[$field_definition->id()]['references'][$referenced_entity->id()]['children'] = $this->getChildren($referenced_entity);
+      }
     }
 
     return $form_element;