Authcache Debug shows wrong no-cache reason after redirect

Authcache does not save pages to the cache, if they are redirects (e.g. drupal_goto() called or Location: header on response). When a page request was cancelled due to a redirect Authcache Debug sets a cookie on the response explaining the reason for the cancellation. This cookie is read and cleared the next time the debug widget is shown on a page.

However because the debug widget is not run on redirect-responses, the cancellation reason is shown to the user on the next page request, which happens to be the target location of the preceding redirect. This is misleading.