Issue #3226791: Validation error saving untranslatable Media reference field

core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php

@@ -1008,6 +1008,10 @@ public static function validateRequired(array $element, FormStateInterface $form
     if (in_array([static::class, 'removeItem'], $form_state->getSubmitHandlers(), TRUE)) {
       return;
     }
+    // If the field is not accessible, this validation isn't needed.
+    if (isset($element['#access']) && !$element['#access']) {
+      return;
+    }
 
     // If user has no access, the validation isn't needed.
     if (isset($element['#access']) && !$element['#access']) {