core/modules/comment/comment.module |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 76f2836..a2f5251 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -458,7 +458,7 @@ function theme_comment_block($variables) {
  */
 function comment_entity_view_alter(&$build, EntityInterface $entity, EntityDisplay $display) {
   // Add the comment page number to the cache key if render caching is enabled.
-  if (isset($build['#cache'])) {
+  if (isset($build['#cache']) && isset($build['#cache']['keys'])) {
     $request = \Drupal::request();
     foreach ($entity->getProperties() as $field_name => $field) {
       // @todo Support multiple unique comment pagers once