diff --git a/core/lib/Drupal/Core/Config/ConfigFactory.php b/core/lib/Drupal/Core/Config/ConfigFactory.php
index 61328a2..b295297 100644
--- a/core/lib/Drupal/Core/Config/ConfigFactory.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactory.php
@@ -226,15 +226,11 @@ protected function loadOverrides(array $names) {
    *   The key of the cached config object to update.
    */
   protected function propagateCacheableDependencyOverrides($cache_key) {
-    $overrides = ['contexts' => [], 'tags' => [], 'max_age' => Cache::PERMANENT];
     foreach ($this->configFactoryOverrides as $override) {
-      $overrides['contexts'] = Cache::mergeContexts($overrides['contexts'], $override->getCacheContexts());
-      $overrides['tags'] = Cache::mergeTags($overrides['tags'], $override->getCacheTags());
-      $overrides['max_age'] = Cache::mergeMaxAges($overrides['max_age'], $override->getCacheMaxAge());
+      $this->cache[$cache_key]->addRuntimeCacheContexts($override->getCacheContexts());
+      $this->cache[$cache_key]->addRuntimeCacheTags($override->getCacheTags());
+      $this->cache[$cache_key]->setRuntimeCacheMaxAge($override->getCacheMaxAge());
     }
-    $this->cache[$cache_key]->addRuntimeCacheContexts($overrides['contexts']);
-    $this->cache[$cache_key]->addRuntimeCacheTags($overrides['tags']);
-    $this->cache[$cache_key]->setRuntimeCacheMaxAge($overrides['max_age']);
   }
 
   /**
diff --git a/core/modules/config/src/Tests/CacheContextConfigOverrideTest.php b/core/modules/config/src/Tests/CacheContextConfigOverrideTest.php
index 38cbb42..90aee2a 100644
--- a/core/modules/config/src/Tests/CacheContextConfigOverrideTest.php
+++ b/core/modules/config/src/Tests/CacheContextConfigOverrideTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\config\Tests;
 
+use Drupal\config_override_test\Cache\PirateDayCacheContext;
 use Drupal\Core\Cache\Cache;
 use Drupal\simpletest\KernelTestBase;
 
@@ -35,8 +36,8 @@ public function testConfigOverride() {
 
     // Check that the cacheable properties are correct.
     $this->assertEqual(['pirate_day'], $config->getCacheContexts());
-    $this->assertEqual(['config:system.theme'], $config->getCacheTags());
-    $this->assertEqual(Cache::PERMANENT, $config->getCacheMaxAge());
+    $this->assertEqual(['config:system.theme', 'pirate-day-tag'], $config->getCacheTags());
+    $this->assertEqual(PirateDayCacheContext::PIRATE_DAY_MAX_AGE, $config->getCacheMaxAge());
   }
 
 }
diff --git a/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php b/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
index 44c344f..80e6000 100644
--- a/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
+++ b/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
@@ -17,6 +17,11 @@
 class PirateDayCacheContext implements CacheContextInterface {
 
   /**
+   * The length of Pirate Day. It lasts 24 hours.
+   */
+  const PIRATE_DAY_MAX_AGE = 86400;
+
+  /**
    * {@inheritdoc}
    */
   public static function getLabel() {
diff --git a/core/modules/config/tests/config_override_test/src/PirateDayCacheContextConfigOverride.php b/core/modules/config/tests/config_override_test/src/PirateDayCacheContextConfigOverride.php
index 20f8303..f7e016d 100644
--- a/core/modules/config/tests/config_override_test/src/PirateDayCacheContextConfigOverride.php
+++ b/core/modules/config/tests/config_override_test/src/PirateDayCacheContextConfigOverride.php
@@ -8,7 +8,6 @@
 namespace Drupal\config_override_test;
 
 use Drupal\config_override_test\Cache\PirateDayCacheContext;
-use Drupal\Core\Cache\Cache;
 use Drupal\Core\Config\ConfigFactoryOverrideInterface;
 use Drupal\Core\Config\StorageInterface;
 
@@ -56,14 +55,14 @@ public function getCacheContexts() {
    * {@inheritdoc}
    */
   public function getCacheTags() {
-    return [];
+    return ['pirate-day-tag'];
   }
 
   /**
    * {@inheritdoc}
    */
   public function getCacheMaxAge() {
-    return Cache::PERMANENT;
+    return PirateDayCacheContext::PIRATE_DAY_MAX_AGE;
   }
 
 }