diff -u b/core/lib/Drupal/Core/Entity/EntityType.php b/core/lib/Drupal/Core/Entity/EntityType.php
--- b/core/lib/Drupal/Core/Entity/EntityType.php
+++ b/core/lib/Drupal/Core/Entity/EntityType.php
@@ -396,13 +396,13 @@
     // not defined in the entity annotation.
     if (!$this->revision_metadata_keys) {
       $base_fields = \Drupal::service('entity_field.manager')->getBaseFieldDefinitions($this->id());
-      if ((isset($base_fields['revision_uid']) && $revision_user = $base_fields['revision_uid']) || (isset($base_fields['revision_user']) && $revision_user = $base_fields['revision_user'])) {
+      if ((isset($base_fields['revision_uid']) && $revision_user = 'revision_uid') || (isset($base_fields['revision_user']) && $revision_user = 'revision_user')) {
         $this->revision_metadata_keys['revision_user'] = $revision_user;
       }
-      if ((isset($base_fields['revision_timestamp']) && $revision_timestamp = $base_fields['revision_timestamp']) || (isset($base_fields['revision_created'])) && $revision_timestamp = $base_fields['revision_created']) {
+      if ((isset($base_fields['revision_timestamp']) && $revision_timestamp = 'revision_timestamp') || (isset($base_fields['revision_created'])) && $revision_timestamp = 'revision_created') {
         $this->revision_metadata_keys['revision_created'] = $revision_timestamp;
       }
-      if ((isset($base_fields['revision_log']) && $revision_log = $base_fields['revision_log']) || (isset($base_fields['revision_log_message']) && $revision_log = $base_fields['revision_log_message'])) {
+      if ((isset($base_fields['revision_log']) && $revision_log = 'revision_log') || (isset($base_fields['revision_log_message']) && $revision_log = 'revision_log_message')) {
         $this->revision_metadata_keys['revision_log_message'] = $revision_log;
       }
     }