core/lib/Drupal/Core/Form/FormBuilder.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index d82c8c4..bb3bfee 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -615,6 +615,11 @@ public function prepareForm($form_id, &$form, FormStateInterface &$form_state) {
       $form['#action'] = $this->buildFormAction();
     }
 
+    // If the form method is specified in the form, pass it on to FormState.
+    if (isset($form['#method'])) {
+      $form_state->setMethod($form['#method']);
+    }
+
     // Fix the form method, if it is 'get' in $form_state, but not in $form.
     if ($form_state->isMethodType('get') && !isset($form['#method'])) {
       $form['#method'] = 'get';