Hi,
I have created a module for the drop-down list that the user can update the field value using form and Ajax, and it works fine except for the first row of the view. When I change the first row, it will throw an error message saying Symfony\Component\HttpKernel\Exception\HttpException: The specified #ajax callback is empty or not callable. in Drupal\Core\Form\FormAjaxResponseBuilder->buildResponse() (line 67 of /var/www5/web/core/lib/Drupal/Core/Form/FormAjaxResponseBuilder.php).