diff --git a/core/modules/node/src/NodeForm.php b/core/modules/node/src/NodeForm.php
index 30a2562..032a8e8 100644
--- a/core/modules/node/src/NodeForm.php
+++ b/core/modules/node/src/NodeForm.php
@@ -378,7 +378,8 @@ public function buildEntity(array $form, FormStateInterface $form_state) {
     $entity = parent::buildEntity($form, $form_state);
     // A user might assign the node author by entering a user name in the node
     // form, which we then need to translate to a user ID.
-    if (!$form_state->isValueEmpty('uid') && $account = User::load($form_state->getValue('uid')[0]['target_id'])) {
+    // @todo: Remove it when https://www.drupal.org/node/2322525 is pushed.
+    if (!empty($form_state->getValue('uid')[0]['target_id']) && $account = User::load($form_state->getValue('uid')[0]['target_id'])) {
       $entity->setOwnerId($account->id());
     }
     else {
diff --git a/core/modules/node/src/Tests/PagePreviewTest.php b/core/modules/node/src/Tests/PagePreviewTest.php
index 3a89473..71f39aa 100644
--- a/core/modules/node/src/Tests/PagePreviewTest.php
+++ b/core/modules/node/src/Tests/PagePreviewTest.php
@@ -175,6 +175,10 @@ function testPagePreview() {
    * Checks the node preview functionality, when using revisions.
    */
   function testPagePreviewWithRevisions() {
+    // Revision Log field is accessible to administrators only.
+    $admin_user = $this->drupalCreateUser(array('administer nodes', 'edit own page content', 'create page content'));
+    $this->drupalLogin($admin_user);
+
     $title_key = 'title[0][value]';
     $body_key = 'body[0][value]';
     $term_key = $this->field_name;