diff --git a/core/modules/rdf/rdf.module b/core/modules/rdf/rdf.module
index 1beb1a1..86aa0a0 100644
--- a/core/modules/rdf/rdf.module
+++ b/core/modules/rdf/rdf.module
@@ -440,11 +440,16 @@ function rdf_preprocess_comment(&$variables) {
   // Adds RDFa markup for the relation between the comment and its author.
   $author_mapping = $mapping->getPreparedFieldMapping('uid');
   if (!empty($author_mapping)) {
-    $author_attributes = array('rel' => $author_mapping['properties']);
-    // Wraps the author variable and the submitted variable which are both
-    // available in comment.html.twig.
-    $variables['author'] = SafeMarkup::set('<span ' . new Attribute($author_attributes) . '>' . $variables['author'] . '</span>');
-    $variables['submitted'] = SafeMarkup::set('<span ' . new Attribute($author_attributes) . '>' . $variables['submitted'] . '</span>');
+    // Wraps the 'author' and 'submitted' variables which are both available in
+    // comment.html.twig.
+    foreach (['author', 'submitted'] as $variable) {
+      $variables[$variable] = [
+        '#type' => 'markup',
+        '#tag' => 'span',
+        '#attributes' => ['rel' => $author_mapping['properties']],
+        '#value' => $variables[$variable]
+      ];
+    }
   }
   // Adds RDFa markup for the date of the comment.
   $created_mapping = $mapping->getPreparedFieldMapping('created');
@@ -457,11 +462,15 @@ function rdf_preprocess_comment(&$variables) {
       '#theme' => 'rdf_metadata',
       '#metadata' => array($date_attributes),
     );
-    $created_metadata_markup = drupal_render($rdf_metadata);
     // Appends the markup to the created variable and the submitted variable
     // which are both available in comment.html.twig.
-    $variables['created'] = SafeMarkup::set(SafeMarkup::escape($variables['created']) . $created_metadata_markup);
-    $variables['submitted'] = SafeMarkup::set($variables['submitted'] . $created_metadata_markup);
+    foreach (['created', 'submitted'] as $variable) {
+      $variables[$variable] = [
+        // Ensure the original variable is represented as a render array.
+        !is_array($variables[$variable]) ? ['#markup' => $variables[$variable]] : $variables[$variable],
+        $rdf_metadata,
+      ];
+    }
   }
   $title_mapping = $mapping->getPreparedFieldMapping('subject');
   if (!empty($title_mapping)) {