diff --git a/core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php b/core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php
index 22e6c10e02..a6755abf2b 100644
--- a/core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php
+++ b/core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php
@@ -53,9 +53,10 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
       ->setClass(DateTimeComputed::class)
       ->setSetting('date source', 'value');
 
+    // @todo Write a comment on why we can't use the $field_definition here.
     $properties['end_value'] = DataDefinition::create('datetime_iso8601')
       ->setLabel(t('End date value'))
-      ->setRequired(!$field_definition->getSetting('optional_end_date'));
+      ->setRequired(FALSE);
 
     $properties['end_date'] = DataDefinition::create('any')
       ->setLabel(t('Computed end date'))
@@ -109,6 +110,7 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
 
     // Just pick a date in the past year. No guidance is provided by this Field
     // type.
+    // @todo Do we need to update this?
     $start = REQUEST_TIME - mt_rand(0, 86400 * 365) - 86400;
     $end = $start + 86400;
     if ($type == static::DATETIME_TYPE_DATETIME) {
diff --git a/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php b/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
index 85fda9ba53..996b71c456 100644
--- a/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
+++ b/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
@@ -19,6 +19,7 @@ class DateRangeWidgetBase extends DateTimeWidgetBase {
    */
   public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
     $element = parent::formElement($items, $delta, $element, $form, $form_state);
+    $optional_end_date = $this->getFieldSetting('optional_end_date');
 
     // Wrap all of the select elements with a fieldset.
     $element['#theme_wrappers'][] = 'fieldset';
@@ -27,9 +28,13 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     $element['value']['#title'] = $this->t('Start date');
 
     $element['end_value'] = [
-      '#title' => $this->t('End date'),
+      '#title' => $optional_end_date ? $this->t('End date (optional)'): $this->t('End date'),
     ] + $element['value'];
 
+    if ($element['#required'] && $optional_end_date) {
+      $element['end_value']['#required'] = FALSE;
+    }
+
     if ($items[$delta]->start_date) {
       /** @var \Drupal\Core\Datetime\DrupalDateTime $start_date */
       $start_date = $items[$delta]->start_date;