diff --git a/js/leaflet.drupal.js b/js/leaflet.drupal.js
index e4e14e0..6e2e3e2 100644
--- a/js/leaflet.drupal.js
+++ b/js/leaflet.drupal.js
@@ -122,9 +122,21 @@
                   const url = content.data('leaflet-ajax-popup');
                   Drupal.ajax({url: url}).execute()
                     .done(function(data) {
+                      // The response may contain add_css/add_js/settings
+                      // commands ahead of the actual content, so locate the
+                      // insert command instead of assuming it's data[0].
+                      // https://www.drupal.org/project/leaflet/issues/3456692
+                      const insert_command = Array.isArray(data) ?
+                        data.find(function(command) { return command.command === 'insert'; }) :
+                        null;
+                      if (!insert_command) {
+                        e.popup.close();
+                        return;
+                      }
+
                       // Copy the html we received via AJAX to the popup, so we won't
-                      // have to make another AJAX call (#see 3258780).
-                      e.popup.setContent(data[0].data);
+                      // have to make another AJAX call.
+                      e.popup.setContent(insert_command.data);
 
                       // Attach drupal behaviors on new content.
                       Drupal.attachBehaviors(element, drupalSettings);