diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php
index c410c54331..2a6caa9c8d 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php
@@ -76,10 +76,12 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
 
       // $complete_form['order_items']['widget']['entities'][0]['form']['inline_entity_form']['field_licensed_used_by']['widget'][0]['target_id']
       $ref = $form;
-      foreach ($element['#array_parents'] as $parent_key) {
-        $ref = $ref[$parent_key];
-        if (!empty($ref['#entity'])) {
-          $entity = $ref['#entity'];
+      if (isset($element['#array_parents'])) {
+        foreach ($element['#array_parents'] as $parent_key) {
+          $ref = $ref[$parent_key];
+          if (!empty($ref['#entity'])) {
+            $entity = $ref['#entity'];
+          }
         }
       }