diff -u b/core/lib/Drupal/Core/Config/ConfigFactory.php b/core/lib/Drupal/Core/Config/ConfigFactory.php
--- b/core/lib/Drupal/Core/Config/ConfigFactory.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactory.php
@@ -61,7 +61,7 @@
     //   be slow in PHP).
     if (!is_object($this->configObject)) {
       $class = $this->container->getParameter('config.object');
-      $this->configObject = new $class($this->container->get('config.manager'));      
+      $this->configObject = new $class($this->container->get('config.manager')); 
     }
     return $this->configObject;
   }
diff -u b/core/modules/config/config_test/config_test.module b/core/modules/config/config_test/config_test.module
--- b/core/modules/config/config_test/config_test.module
+++ b/core/modules/config/config_test/config_test.module
@@ -82,7 +82,9 @@
  *   The ID of the ConfigTest object to load.
  */
 function config_test_load($id) {
-  $config = config('config_test.dynamic.' . $id);
+  // config returns the config object used to load all config in order to use
+  // this safely later we need to clone the object to protect it from change.
+  $config = clone config('config_test.dynamic.' . $id);
   // @todo Requires a more reliable + generic method to check for whether the
   //   configuration object exists.
   if ($config->get('id') === NULL) {