diff --git a/core/lib/Drupal/Core/Render/Element/FormElement.php b/core/lib/Drupal/Core/Render/Element/FormElement.php
index b2d9b90..173a55c 100644
--- a/core/lib/Drupal/Core/Render/Element/FormElement.php
+++ b/core/lib/Drupal/Core/Render/Element/FormElement.php
@@ -130,9 +130,7 @@ public static function processAutocomplete(&$element, FormStateInterface $form_s
         $element['#attributes']['class'][] = 'form-autocomplete';
         $metadata->addAttachments(['library' => ['core/drupal.autocomplete']]);
         // Provide a data attribute for the JavaScript behavior to bind to.
-        // Prefix the uri with the script name to bypass relative urls - forcing
-        // non-clean urls. e.g. index.php/some/path.
-        $element['#attributes']['data-autocomplete-path'] = \Drupal::request()->getScriptName() . '/' . $url->getGeneratedUrl();
+        $element['#attributes']['data-autocomplete-path'] = $url->getGeneratedUrl();
         $metadata = $metadata->merge($url);
       }
       $metadata