Debug Access is being cached

I disabled the debug feature for some roles in appearance settings (debugging), but the debug blocks are still available for unselected roles.
@see in sites/all/themes/omega/alpha/includes/alpha.inc lines 350ff in

function alpha_grid_include($columns) {
[...]
the value for $theme->settings['debug']['access'] is being cached 

Solved that problem with the following workaround:

Implemented hook_alpha_alter to override the cached settings:

function MYTHEME_alpha_alter(&$data, $context1, $context2) {
  $roles = array_keys(array_filter(alpha_theme_get_setting('alpha_debug_grid_roles', array(), 'MYTHEME')));
  $data->settings['debug']['access'] = alpha_debug_access($GLOBALS['user'], $roles);
}