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
@@ -98,7 +98,6 @@
    */
   public function disableOverrides() {
     $this->useOverrides = FALSE;
-    $this->reset();
   }
 
   /**
@@ -106,7 +105,6 @@
    */
   public function enableOverrides() {
     $this->useOverrides = TRUE;
-    $this->reset();
   }
 
   /**
@@ -316,12 +314,13 @@
    *   The cache key.
    */
   public function getCacheKey($name) {
-    if (isset($this->language)) {
-      return $this->language->id . ":$name";
-    }
-    else {
-      return $name;
+    $can_override = $this->canOverride($name);
+    $cache_key = $name . ':' . ($can_override ? 'overrides' : 'raw');
+
+    if ($can_override && isset($this->language)) {
+      $cache_key =  $cache_key . ':' . $this->language->id;
     }
+    return $cache_key;
   }
 
   /**
@@ -335,8 +334,7 @@
    */
   public function getCacheKeys($name) {
     return array_filter(array_keys($this->cache), function($key) use ($name) {
-      // Match only $name directly, or LANGCODE:$name.
-      return preg_match('/^([a-z]+:)?' . preg_quote($name) . '$/', $key);
+      return preg_match('/^' . preg_quote($name) . ':/', $key);
     });
   }