diff --git a/core/lib/Drupal/Core/Render/Renderer.php b/core/lib/Drupal/Core/Render/Renderer.php
index c539e3a..e837b18 100644
--- a/core/lib/Drupal/Core/Render/Renderer.php
+++ b/core/lib/Drupal/Core/Render/Renderer.php
@@ -669,9 +669,10 @@ protected function cacheSet(array &$elements, array $pre_bubbling_elements) {
     // and render caching of forms prevents this from happening.
     // @todo remove the isMethodSafe() check when
     //       https://www.drupal.org/node/2367555 lands.
-    if (!$this->requestStack->getCurrentRequest()->isMethodSafe() || !$cid = $this->createCacheID($elements)) {
+    if (!$this->requestStack->getCurrentRequest()->isMethodSafe()) {
       return FALSE;
     }
+    $cid = $this->createCacheID($elements);
 
     $data = $this->getCacheableRenderArray($elements);
 
@@ -682,6 +683,45 @@ protected function cacheSet(array &$elements, array $pre_bubbling_elements) {
     // Calculate pre_bubbling_cid.
     $pre_bubbling_cid = $this->createCacheID($pre_bubbling_elements);
 
+    // Placeholdering at work, check if we can placeholder.
+    if (!isset($pre_bubbling_elements['#cache_no_placeholder']) && $pre_bubbling_cid && ($cid || isset($pre_bubbling_elements['#pre_render_cache']))) {
+      // Check if we want to placeholder.
+      if (!empty($elements['#cache_placeholder']) || (isset($elements['#cache']['max-age']) && $elements['#cache']['max-age'] == 0)) {
+        $elements = $this->createRenderCacheArrayPlaceholder($pre_bubbling_elements, $elements);
+
+        // Now update the #cache_redirect array or create it.
+        // @todo Consolidate logic using a helper function.
+        $redirect_data = [
+          '#cache' => [
+            'keys' => [],
+            'contexts' => [],
+            'tags' => [],
+          ],
+        ];
+
+        if ($stored_cache_redirect = $cache->get($pre_bubbling_cid)) {
+          $redirect_data['#cache']['keys'] = $stored_cache_redirect->data['#cache']['keys'];
+          $redirect_data['#cache']['contexts'] = $stored_cache_redirect->data['#cache']['contexts'];
+          $redirect_data['#cache']['tags'] = $stored_cache_redirect->data['#cache']['tags'];
+          if (isset($stored_cache_redirect->data['#cache']['#cache_placeholder'])) {
+            $redirect_data['#cache_placeholder'] = $stored_cache_redirect->data['#cache_placeholder'];
+          }
+        }
+        if (empty($redirect_data['#cache_placeholder'])) {
+          $redirect_data['#cache_redirect'] = TRUE;
+          $redirect_data['#cache_placeholder'] = TRUE;
+          $cache->set($pre_bubbling_cid, $redirect_data, Cache::PERMANENT, Cache::mergeTags($redirect_data['#cache']['tags'], ['rendered']));
+        }
+
+        return;
+      }
+    }
+
+    // Early return if $cid is empty.
+    if (!$cid) {
+      return FALSE;
+    }
+
     // Two-tier caching: detect different CID post-bubbling, create redirect,
     // update redirect if different set of cache contexts.
     // @see ::doRender()
@@ -819,6 +859,12 @@ protected function cacheSet(array &$elements, array $pre_bubbling_elements) {
             'tags' => Cache::mergeTags($stored_cache_tags, $data['#cache']['tags']),
           ],
         ];
+
+        // Ensure #cache_placeholder setting remains.
+        if (isset($stored_cache_redirect->data['#cache']['#cache_placeholder'])) {
+          $redirect_data['#cache_placeholder'] = $stored_cache_redirect->data['#cache_placeholder'];
+        }
+
         $cache->set($pre_bubbling_cid, $redirect_data, $expire, Cache::mergeTags($redirect_data['#cache']['tags'], ['rendered']));
       }
 
diff --git a/core/modules/system/src/Plugin/Block/SystemBrandingBlock.php b/core/modules/system/src/Plugin/Block/SystemBrandingBlock.php
index f8a7ed3..a86fccc 100644
--- a/core/modules/system/src/Plugin/Block/SystemBrandingBlock.php
+++ b/core/modules/system/src/Plugin/Block/SystemBrandingBlock.php
@@ -186,6 +186,11 @@ public function build() {
 
     usleep(2000*1000);
 
+    // Bubble up that this is uncacheable.
+    $build['site_slogan']['#cache']['max-age'] = 0;
+    $build['site_slogan']['#cache']['contexts'] = ['user'];
+    $build['site_slogan']['#debug'] = TRUE;
+
     return $build;
   }
 
@@ -203,7 +208,8 @@ public function getCacheTags() {
    * {@inheritdoc}
    */
   public function getCacheContexts() {
-    return [ 'route', 'user', 'languages' ];
+    return [];
+    //return [ 'route', 'user', 'languages' ];
   }
 
 
@@ -211,6 +217,7 @@ public function getCacheContexts() {
    * {@inheritdoc}
    */
   public function getCacheMaxAge() {
-    return 0;
+//    return 0;
+    return Cache::PERMANENT;
   }
 }
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 88f9023..4124b2f 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -776,7 +776,7 @@ function system_preprocess_block(&$variables) {
       }
       $variables['site_slogan'] = '';
       if ($variables['content']['site_slogan']['#access'] && $variables['content']['site_slogan']['#markup']) {
-        $variables['site_slogan'] = $variables['content']['site_slogan']['#markup'];
+        $variables['site_slogan'] = drupal_render($variables['content']['site_slogan']);
       }
       break;