diff --git a/core/lib/Drupal/Core/Entity/EntityViewBuilder.php b/core/lib/Drupal/Core/Entity/EntityViewBuilder.php
index 71d3839..bb375ad 100644
--- a/core/lib/Drupal/Core/Entity/EntityViewBuilder.php
+++ b/core/lib/Drupal/Core/Entity/EntityViewBuilder.php
@@ -93,8 +93,10 @@ public static function createInstance(ContainerInterface $container, EntityTypeI
   public function buildContent(array $entities, array $displays, $view_mode, $langcode = NULL) {
     $entities_by_bundle = array();
     foreach ($entities as $id => $entity) {
-      // Remove previously built content, if exists.
-      $entity->content = array(
+      if (empty($entity->content)) {
+        $entity->content = array();
+      }
+      $entity->content += array(
         '#view_mode' => $view_mode,
       );
       // Initialize the field item attributes for the fields being displayed.
@@ -195,11 +197,11 @@ public function entityViewBuilderPreRender(array $elements) {
     $this->moduleHandler->alter('entity_view_mode', $view_mode, $entity, $context);
 
     // Get the corresponding display settings.
-    $display = EntityViewDisplay::collectRenderDisplays($entity, $view_mode);
+    $display = EntityViewDisplay::collectRenderDisplay($entity, $view_mode);
 
     // Build field renderables.
     $entity->content = $elements;
-    $this->buildContent(array($entity), array($bundle => $display), $view_mode, $langcode);
+    $this->buildContent(array($entity->id() => $entity), array($bundle => $display), $view_mode, $langcode);
     $view_mode = isset($entity->content['#view_mode']) ? $entity->content['#view_mode'] : $view_mode;
 
     $this->moduleHandler()->invokeAll($view_hook, array($entity, $display, $view_mode, $langcode));
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 0070378..51d0561 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -1312,17 +1312,14 @@ function comment_preview(CommentInterface $comment, array &$form_state) {
     // includes the comment reply form, which contains the comment preview and
     // therefore the rendered parent entity. This results in an infinite loop of
     // parent entity output rendering the comment form and the comment form
-    // rendering the parent entity. To prevent this infinite loop we temporarily
-    // set the value of the comment field on the rendered entity to hidden
+    // rendering the parent entity. To prevent this infinite loop we clone
+    // the commented entity and change the value of the comment field to hidden
     // before calling entity_view(). That way when the output of the commented
-    // entity is rendered, it excludes the comment field output. As objects are
-    // always addressed by reference we ensure changes are not lost by setting
-    // the value back to its original state after the call to entity_view().
+    // entity is rendered, it excludes the comment field output.
+    $entity = clone $entity;
     $field_name = $comment->getFieldName();
-    $original_status = $entity->get($field_name)->status;
     $entity->get($field_name)->status = COMMENT_HIDDEN;
     $build = entity_view($entity, 'full');
-    $entity->get($field_name)->status = $original_status;
   }
 
   $preview_build['comment_output_below'] = $build;