Undefined index: #id in views_attach_form_alter()

I'm getting the following PHP notice in various logfiles, including any Drush operation:

WD php: Notice: Undefined index: #id in views_attach_form_alter() (line 264 of /var/www/drupal/sites/all/modules/views_attach/views_attach.module).

I'm not aware of any serious problems this would cause, but I'd like to get rid of these messages (without decreasing the PHP loglevel even further; currently using error_reporting = E_ERROR & E_RECOVERABLE_ERROR & E_WARNING).

Thanks!