diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/field/widget/TaxonomyAutocompleteWidget.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/field/widget/TaxonomyAutocompleteWidget.php
index 90d7b1d..bc7308b 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/field/widget/TaxonomyAutocompleteWidget.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/field/widget/TaxonomyAutocompleteWidget.php
@@ -116,7 +116,7 @@ public function massageFormValues(array $values, array $form, array &$form_state
           'vid' => $vocabulary->id(),
           'name' => $value,
         ));
-        $item = array('target_id' => 0, 'entity' => $term);
+        $item = array('target_id' => NULL, 'entity' => $term);
       }
       $items[] = $item;
     }