Issue #1880922 by yched: Remnants of entity_view_prepared() flag.

core/modules/node/lib/Drupal/node/NodeFormController.php

@@ -399,18 +399,4 @@ public function delete(array $form, array &$form_state) {
     $form_state['redirect'] = array('node/' . $node->nid . '/delete', array('query' => $destination));
   }
 
-  /**
-   * Overrides \Drupal\Core\Entity\EntityFormController::buildEntity().
-   */
-  public function buildEntity(array $form, array &$form_state) {
-    $node = parent::buildEntity($form, $form_state);
-    // If the node went through 'Preview', it got stored back in $form_state
-    // with values out of the 'prepare_view' steps, and with the
-    // entity_view_prepared flag set. Since buildEntity() resets the values to
-    // those in the form submission, the entity_view_prepared flag needs to be
-    // reset too so that the next 'Preview' can work on a consistent $node.
-    unset($node->entity_view_prepared);
-    return $node;
-  }
-
 }