Missing element children

I was trying to use this module with custom pages (page_manager + panels + ctools_block)

i noticed that this formatter didn't render in a ctools_block, after some debug i noticed that on EntityField.php line 172 (ctool_block module) it only allows access to block if there is a element children.

$build = $entity->get($this->fieldName)->view($this->configuration['formatter']);
          // If there are actual renderable children, grant access.
          if (Element::children($build)) {
            return AccessResult::allowed();
          }