diff --git a/core/lib/Drupal/Core/Render/Element/Markup.php b/core/lib/Drupal/Core/Render/Element/Markup.php
index 650a90c..c1763a6 100644
--- a/core/lib/Drupal/Core/Render/Element/Markup.php
+++ b/core/lib/Drupal/Core/Render/Element/Markup.php
@@ -106,7 +106,6 @@ public static function ensureMarkupIsSafe(array $elements) {
 
     if (!empty($elements['#plain_text'])) {
       $elements['#markup'] = SafeString::create(HtmlUtility::escape($elements['#plain_text']));
-      unset($elements['#plain_text']);
     }
     elseif (!SafeMarkup::isSafe($elements['#markup'])) {
       // The default behaviour is to XSS filter using the admin tag list.