diff --git a/drupal/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php b/drupal/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
index bcaafaf..a0ec644 100644
--- a/drupal/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
+++ b/drupal/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
@@ -41,14 +41,15 @@ class AutocompleteWidget extends AutocompleteWidgetBase {
   public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, array &$form_state) {
     // We let the Field API handles multiple values for us, only take care of
     // the one matching our delta.
+    $item = clone $items;
     if (isset($items[$delta])) {
-      $items->setValue(array($items[$delta]->getValue()));
+      $item->setValue(array($items[$delta]->getValue()));
     }
     else {
-      $items->setValue(array());
+      $item->setValue(array());
     }
 
-    return parent::formElement($items, $delta, $element, $form, $form_state);
+    return parent::formElement($item, $delta, $element, $form, $form_state);
   }
 
   /**