diff -u b/core/lib/Drupal/Core/Cache/MemoryBackend.php b/core/lib/Drupal/Core/Cache/MemoryBackend.php
--- b/core/lib/Drupal/Core/Cache/MemoryBackend.php
+++ b/core/lib/Drupal/Core/Cache/MemoryBackend.php
@@ -224,9 +224,9 @@
    * Prevents data stored in memory backends from being serialized.
    */
   public function __sleep() {
-    return array_filter($this->traitSleep(), function($var) {
-      return '_serviceIds' == $var;
-    });
+    // The injected serializer service needs to be recovered.
+    $this->traitSleep();
+    return ['_serviceIds'];
   }
 
   /**