Issue #3129547 by AdamPS: Error for entities without langcode field

modules/manage_display_fix_title/manage_display_fix_title.module

@@ -89,5 +89,5 @@ function quickedit_preprocess_entity_page_title(&$variables) {
   }
 
   $label_field = $entity->getEntityType()->getKey('label');
-  $variables['attributes']['data-quickedit-field-id'] = $entity->getEntityTypeId() . '/' . $entity->id() . '/' . $label_field . '/' . $entity->get('langcode')->value . '/' . $variables['view_mode'];
+  $variables['attributes']['data-quickedit-field-id'] = $entity->getEntityTypeId() . '/' . $entity->id() . '/' . $label_field . '/' . $entity->language()->getId() . '/' . $variables['view_mode'];
 }