diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index b510d1b..060ea12 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -534,7 +534,7 @@ public function prepareForm($form_id, &$form, FormStateInterface &$form_state) {
 
     // Only update the action if it is not already set.
     if (!isset($form['#action'])) {
-      $form['#action'] = $this->requestStack->getCurrentRequest()->getRequestUri();
+      $form['#action'] = $this->requestStack->getMasterRequest()->getRequestUri();
     }
 
     // Fix the form method, if it is 'get' in $form_state, but not in $form.