diff -u b/core/modules/config/src/Form/ConfigSync.php b/core/modules/config/src/Form/ConfigSync.php
--- b/core/modules/config/src/Form/ConfigSync.php
+++ b/core/modules/config/src/Form/ConfigSync.php
@@ -178,8 +178,12 @@
         }
       }
       sort($change_list);
-      $change_list_text = implode(', ', $change_list);
-      drupal_set_message($this->t('Your current configuration has changed. Changes to these configuration items will be lost on the next synchronization: %changes', array('%changes' => $change_list_text)), 'warning');
+      $change_list_render = array(
+        '#theme' => 'item_list',
+        '#items' => $change_list,
+      );
+      $change_list_html = drupal_render($change_list_render);
+      drupal_set_message($this->t('Your current configuration has changed. Changes to these configuration items will be lost on the next synchronization: !changes', array('!changes' => $change_list_html)), 'warning');
     }
     $form['actions'] = array('#type' => 'actions');
     $form['actions']['submit'] = array(