diff -u b/core/misc/ajax.es6.js b/core/misc/ajax.es6.js
--- b/core/misc/ajax.es6.js
+++ b/core/misc/ajax.es6.js
@@ -1021,7 +1021,7 @@
       const settings = response.settings || ajax.settings || drupalSettings;
 
       // Parse response.data into an element collection.
-      const $newContent = $($.parseHTML(response.data));
+      const $newContent = $($.parseHTML(response.data, true));
 
       // If removing content from the wrapper, detach behaviors first.
       switch (method) {
diff -u b/core/misc/ajax.js b/core/misc/ajax.js
--- b/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -481,7 +481,7 @@
 
       var settings = response.settings || ajax.settings || drupalSettings;
 
-      var $newContent = $($.parseHTML(response.data));
+      var $newContent = $($.parseHTML(response.data, true));
 
       switch (method) {
         case 'html':