diff -u b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidgetBase.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidgetBase.php
--- b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidgetBase.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidgetBase.php
@@ -173,11 +173,16 @@
     $bundle_key = $entity_info['entity_keys']['bundle'];
     $label_key = $entity_info['entity_keys']['label'];
 
-    return $entity_manager->getStorageController($target_type)->create(array(
+    $entity = $entity_manager->getStorageController($target_type)->create(array(
       $label_key => $label,
-      $bundle_key => $bundle,
-      'uid' => $uid,
+      $bundle_key => $bundle
     ));
+
+    if ($entity instanceof EntityAuthorInterface) {
+      $entity->setAuthorId($uid);
+    }
+
+    return $entity;
   }
 
   /**
only in patch2:
unchanged:
--- a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Entity/EntityTest.php
+++ b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Entity/EntityTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\entity_test\Entity;
 
 use Drupal\Core\Entity\EntityNG;
+use Drupal\Core\Entity\EntityAuthorInterface;
 use Drupal\Core\Entity\Annotation\EntityType;
 use Drupal\Core\Annotation\Translation;
 use Drupal\Core\Language\Language;
@@ -39,7 +40,7 @@
  *   menu_base_path = "entity-test/manage/%entity_test"
  * )
  */
-class EntityTest extends EntityNG {
+class EntityTest extends EntityNG implements EntityAuthorInterface {
 
   /**
    * The entity ID.
@@ -147,4 +148,26 @@ public static function baseFieldDefinitions($entity_type) {
     );
     return $fields;
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getAuthor() {
+    return $this->get('user_id')->entity;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getAuthorId() {
+    return $this->get('user_id')->value;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setAuthorId($uid) {
+    $this->set('user_id', $uid);
+    return $this;
+  }
 }