og_ui_admin_permissions_after_build disables permissions if you don't include OG_AUTHENTICATED_ROLE in your permission definition

function HOOK_og_permission() {
  
  $perms = array();
  $perms['disabled example'] = array(
    'title' => t('Disabled example'),
    'description' => t('Demonstrates how you cannot enable this permission for specified roles only.'),
    'roles' => array(OG_ADMINISTRATOR_ROLE),
    'default role' => array(OG_ADMINISTRATOR_ROLE),
  );

  $perms['enabled example'] = array(
    'title' => t('Enabled example'),
    'description' => t('Demonstrates how you can now enable this permission.'),
    'roles' => array(OG_AUTHENTICATED_ROLE, OG_ADMINISTRATOR_ROLE),
    'default role' => array(OG_ADMINISTRATOR_ROLE),
  );

  return $perms;
}

I would expect the 'disabled example' perm to allow me to enable it for the administrator role, but that is not the case. This code:

    if ($disable || (empty($perm['roles']) || empty($perm['roles'][OG_AUTHENTICATED_ROLE]))) {
      foreach ($auth_rids as $auth_rid) {
        if (in_array($auth_rid, array_keys($role_names))) {
          $form['checkboxes'][$auth_rid][$key]['#attributes']['disabled'] = TRUE;
        }
      }
    }

From og_ui_admin_permissions_after_build in og_ui.admin.inc will disable all checkboxes if OG_AUTHENTICATED_ROLE is not specified.