diff --git a/core/modules/text/lib/Drupal/text/Plugin/field/widget/TextareaWithSummaryWidget.php b/core/modules/text/lib/Drupal/text/Plugin/field/widget/TextareaWithSummaryWidget.php
index 6861933..0886a5a 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/field/widget/TextareaWithSummaryWidget.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/field/widget/TextareaWithSummaryWidget.php
@@ -74,7 +74,8 @@ function formElement(FieldInterface $items, $delta, array $element, $langcode, a
       '#prefix' => '<div class="text-summary-wrapper">',
       '#suffix' => '</div>',
       '#weight' => -10,
-      '#required' => $required,
+      // Make sure the summary is not required for the default widget.
+      '#required' => $required && !isset($form_state['default_value_widget']),
     );
 
     if (!$this->getFieldSetting('show_summary') && !$required) {