diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index 5e36b19..1245c6f 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -270,7 +270,7 @@ public function buildForm($form_id, FormStateInterface &$form_state) {
     // then passed through
     // \Drupal\Core\Form\FormAjaxResponseBuilderInterface::buildResponse() to
     // build a proper AJAX response.
-    if ($ajax_form_request) {
+    if ($ajax_form_request && $form_state->isProcessingInput()) {
       throw new FormAjaxException($form, $form_state);
     }