diff --git a/cms/static/js/views/pages/container_subviews.js b/cms/static/js/views/pages/container_subviews.js
index b32c86ae8dec..223fde98ef89 100644
--- a/cms/static/js/views/pages/container_subviews.js
+++ b/cms/static/js/views/pages/container_subviews.js
@@ -506,9 +506,13 @@ function($, _, gettext, BaseView, ViewUtils, XBlockViewUtils, MoveXBlockUtils, H
         },
 
         renderTagElements: function(tags, depth, parentId) {
+            /* This function updates the tags in the sidebar of the legacy Unit Outline Page.
+             * It is not used in the mfe version of the Unit Outline. */
+            const parentElement = document.querySelector(`.content-tags-${parentId}`);
+            if (!parentElement) return;
+
             const tagListElement = this;
             tags.forEach(function(tag) {
-                const parentElement = document.querySelector(`.content-tags-${parentId}`);
                 var tagContentElement = document.createElement('div'),
                     tagValueElement = document.createElement('span');