core/lib/Drupal/Core/Render/Renderer.php           | 29 +++++++++++++++-------
 .../Drupal/Tests/Core/Render/RendererTest.php      |  5 +---
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/core/lib/Drupal/Core/Render/Renderer.php b/core/lib/Drupal/Core/Render/Renderer.php
index 40a2a9e..78e2deb 100644
--- a/core/lib/Drupal/Core/Render/Renderer.php
+++ b/core/lib/Drupal/Core/Render/Renderer.php
@@ -174,15 +174,6 @@ protected function doRender(&$elements, $is_root_call = FALSE) {
     }
     static::$stack->push(new BubbleableMetadata());
 
-    // Bubbleable rendering metadata that has configurable defaults.
-    $required_cache_contexts = $this->rendererConfig['required_cache_contexts'];
-    if (isset($elements['#cache']['contexts'])) {
-      $elements['#cache']['contexts'] = Cache::mergeContexts($elements['#cache']['contexts'], $required_cache_contexts);
-    }
-    else {
-      $elements['#cache']['contexts'] = $required_cache_contexts;
-    }
-
     // Try to fetch the prerendered element from cache, run any
     // #post_render_cache callbacks and return the final markup.
     $pre_bubbling_cid = NULL;
@@ -235,11 +226,23 @@ protected function doRender(&$elements, $is_root_call = FALSE) {
     }
 
     // Defaults for bubbleable rendering metadata.
+    $elements['#cache']['contexts'] = isset($elements['#cache']['contexts']) ? $elements['#cache']['contexts'] : array();
     $elements['#cache']['tags'] = isset($elements['#cache']['tags']) ? $elements['#cache']['tags'] : array();
     $elements['#cache']['max-age'] = isset($elements['#cache']['max-age']) ? $elements['#cache']['max-age'] : Cache::PERMANENT;
     $elements['#attached'] = isset($elements['#attached']) ? $elements['#attached'] : array();
     $elements['#post_render_cache'] = isset($elements['#post_render_cache']) ? $elements['#post_render_cache'] : array();
 
+    // Bubbleable rendering metadata that has configurable defaults
+    if ($is_root_call) {
+      $required_cache_contexts = $this->rendererConfig['required_cache_contexts'];
+      if (!empty($elements['#cache']['contexts'])) {
+        $elements['#cache']['contexts'] = Cache::mergeContexts($elements['#cache']['contexts'], $required_cache_contexts);
+      }
+      else {
+        $elements['#cache']['contexts'] = $required_cache_contexts;
+      }
+    }
+
     // Allow #pre_render to abort rendering.
     if (!empty($elements['#printed'])) {
       // The #printed element contains all the bubbleable rendering metadata for
@@ -747,6 +750,14 @@ protected function createCacheID(array $elements) {
 
     if (isset($elements['#cache']['keys'])) {
       $cid_parts = $elements['#cache']['keys'];
+      // Include the required cache contexts in the cache ID.
+      $required_cache_contexts = $this->rendererConfig['required_cache_contexts'];
+      if (!empty($elements['#cache']['contexts'])) {
+        $elements['#cache']['contexts'] = Cache::mergeContexts($elements['#cache']['contexts'], $required_cache_contexts);
+      }
+      else {
+        $elements['#cache']['contexts'] = $required_cache_contexts;
+      }
       if (!empty($elements['#cache']['contexts'])) {
         $contexts = $this->cacheContexts->convertTokensToKeys($elements['#cache']['contexts']);
         $cid_parts = array_merge($cid_parts, $contexts);
diff --git a/core/tests/Drupal/Tests/Core/Render/RendererTest.php b/core/tests/Drupal/Tests/Core/Render/RendererTest.php
index dbcb7fa..59977cb 100644
--- a/core/tests/Drupal/Tests/Core/Render/RendererTest.php
+++ b/core/tests/Drupal/Tests/Core/Render/RendererTest.php
@@ -19,10 +19,7 @@ class RendererTest extends RendererTestBase {
 
   protected $defaultThemeVars = [
     '#cache' => [
-      'contexts' => [
-        'languages:language_interface',
-        'theme',
-      ],
+      'contexts' => [],
       'tags' => [],
       'max-age' => Cache::PERMANENT,
     ],