This snippet expands the details tags whenever a child form field fails browser validation

field_group_form_validation

(function ($, Drupal) {
  Drupal.behaviors.openRequiredWrappers = {
    attach: function (context, settings) {

      // Prevent unnecessary multiple reloads.
      if (context instanceof HTMLDocument) {
        console.log("Test WDDSE-1913");

        var required_items = $('input,textarea,select').filter('[required]');

        required_items.each(function (index, el) {

          // Add event listener that reacts when a form field fails validation.
          $(el).on('invalid', function(e){

            // Expand all collapsed wrappers.
            $(el).parents("details").each(function(index2, wrapper) {
              wrapper.open = true;
            });
          });
        })
      }

    }
  }
})(jQuery,Drupal);