diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index e9ccb3e..2d0152a 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -506,7 +506,7 @@ function template_preprocess_forums(&$variables) {
           }
 
           $row[] = array(
-            'data' => $topic->comment_count . $new_replies,
+            'data' => array('#markup' => $topic->comment_count . $new_replies),
             'class' => array('forum__replies'),
           );
           $row[] = array(
diff --git a/core/modules/forum/src/Tests/ForumIndexTest.php b/core/modules/forum/src/Tests/ForumIndexTest.php
index b9ee537..9b95037 100644
--- a/core/modules/forum/src/Tests/ForumIndexTest.php
+++ b/core/modules/forum/src/Tests/ForumIndexTest.php
@@ -17,6 +17,20 @@
 class ForumIndexTest extends WebTestBase {
 
   /**
+   * User account with access to create forum topics.
+   *
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $webUser;
+
+  /**
+   * User account with access to create replies in a forum topic.
+   *
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $forumUser;
+
+  /**
    * Modules to enable.
    *
    * @var array
@@ -26,15 +40,15 @@ class ForumIndexTest extends WebTestBase {
   protected function setUp() {
     parent::setUp();
 
-    // Create a test user.
-    $web_user = $this->drupalCreateUser(array('create forum content', 'edit own forum content', 'edit any forum content', 'administer nodes'));
-    $this->drupalLogin($web_user);
+    $this->webUser = $this->drupalCreateUser(array('create forum content', 'edit own forum content', 'edit any forum content', 'administer nodes'));
+    $this->forumUser = $this->drupalCreateUser(array('create forum content', 'edit own forum content', 'edit any forum content', 'administer nodes', 'administer comments', 'post comments', 'skip comment approval'));
   }
 
   /**
    * Tests the forum index for published and unpublished nodes.
    */
-  function testForumIndexStatus() {
+  public function testForumIndexStatus() {
+    $this->drupalLogin($this->webUser);
     // The forum ID to use.
     $tid = 1;
 
@@ -68,4 +82,41 @@ function testForumIndexStatus() {
     $this->drupalGet('forum/' . $tid);
     $this->assertNoText($title, 'Unpublished forum topic no longer appears on index.');
   }
+
+  public function testHistory() {
+    $this->drupalLogin($this->webUser);
+    // The forum ID to use.
+    $tid = 1;
+
+    // Create a test node.
+    $title = $this->randomMachineName(20);
+    $edit = array(
+      'title[0][value]' => $title,
+      'body[0][value]' => $this->randomMachineName(200),
+    );
+
+    // Create the forum topic, preselecting the forum ID via a URL parameter.
+    $this->drupalGet("forum/$tid");
+    $this->clickLink(t('Add new @node_type', array('@node_type' => 'Forum topic')));
+    $this->drupalPostForm(NULL, $edit, t('Save and publish'));
+
+    // Login as the forum user to create a reply.
+    $this->drupalLogin($this->forumUser);
+
+    // Create a comment.
+    $edit = array();
+    $edit['comment_body[0][value]'] = $this->randomMachineName();
+
+    $this->drupalGet("forum/$tid");
+    $this->clickLink(t($title));
+    $this->drupalPostForm(NULL, $edit, t('Save'));
+
+    // Verify the new post message link is not escaped.
+    $this->drupalLogin($this->webUser);
+    $this->drupalGet("forum/$tid");
+    $xpath = $this->buildXPathQuery('//td[@class="forum__replies"]/a/span[@class="visually-hidden"]');
+    $new_replies_message = $this->xpath($xpath);
+    $this->assertTrue(!empty($new_replies_message), "The new replies message was found.");
+  }
+
 }