Losing query string on external redirects

When saving a redirect to an external URL i'm losing any and all query strings. I've updated to latest dev and tracked it down to line 462 in redirect.admin.inc:

  ...
  _redirect_extract_url_options($element, $form_state);
  $value = &$form_state['values']['redirect'];

  // Normalize the path.
  $value = drupal_get_normal_path($value, $form_state['values']['language']);
  ...

For now I've commented out _redirect_extract_url_options() and it seems to be working. Would like to get more info on this both from my investigation and the reasons behind that function call.