[support] OG Unsubscribe Access Denied

Greetings,

In OG 5.x-8.1 (presently, but this also affected earlier versions), the unsubscribe URL generated by !url_unsubscribe is /og/unsubscribe/### (where ### is the number of the group node). However, this URL results in an access denied, even for user 1.

I found a few issues that were similar, but not quite right ( http://drupal.org/node/334665, or maybe https://drupal.org/node/562656), so I thought I'd ask here.

Is there a missed a setting that would allow access to the /og/unsubscribe path or is this simply the wrong path? I've tried a few variations on that path, by hand, but every path is denied. OG Access Control, by the way, is not enabled.

Thanks, Brian