diff --git a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
index 3ad1320..e3ec321 100644
--- a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
@@ -128,12 +128,10 @@ protected function makeSubrequest(GetResponseForExceptionEvent $event, $url, $st
 
     if ($url != $request->getBasePath() . '/' && $url != $current_url) {
       if ($request->getMethod() === 'POST') {
-        $sub_request = Request::create($url, 'POST', $this->redirectDestination->getAsArray() + $request->request->all(), $request->cookies->all(), [], $request->server->all());
-        $sub_request->attributes->set('_exception_statuscode', $status_code);
+        $sub_request = Request::create($url, 'POST', $this->redirectDestination->getAsArray() + ['_exception_statuscode' => $status_code] + $request->request->all(), $request->cookies->all(), [], $request->server->all());
       }
       else {
-        $sub_request = Request::create($url, 'GET', $request->query->all() + $this->redirectDestination->getAsArray(), $request->cookies->all(), [], $request->server->all());
-        $sub_request->attributes->set('_exception_statuscode', $status_code);
+        $sub_request = Request::create($url, 'GET', $request->query->all() + $this->redirectDestination->getAsArray() + ['_exception_statuscode' => $status_code], $request->cookies->all(), [], $request->server->all());
       }
 
       try {
diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index 52b24fd..40c598f 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -688,7 +688,7 @@ protected function buildFormAction() {
     //   https://www.drupal.org/node/2505339.
     $request_uri = $this->requestStack->getMasterRequest()->getRequestUri();
 
-    // @todo Remove this unset() once these are removed from the request in
+    // @todo Remove this parsing once these are removed from the request in
     //   https://www.drupal.org/node/2504709.
     $parsed = UrlHelper::parse($request_uri);
     unset($parsed['query'][static::AJAX_FORM_REQUEST], $parsed['query'][MainContentViewSubscriber::WRAPPER_FORMAT]);
diff --git a/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php b/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
index c0bdb1e..ffb2a21 100644
--- a/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
+++ b/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
@@ -147,7 +147,7 @@ public function testHandleWithGetRequest() {
 
     $response = $event->getResponse();
     $result = $response->getContent() . " " . UrlHelper::buildQuery($request->request->all());
-    $this->assertEquals('GET name=druplicon&pass=12345&destination=test ', $result);
+    $this->assertEquals('GET name=druplicon&pass=12345&destination=test&_exception_statuscode=404 ', $result);
   }
 
 }