1. I follow a link to a deleted attachment (like in bug 942406 comment 3): attachment 8337325 [details]. The link is https://bugzilla.mozilla.org/attachment.cgi?id=8337325 2. It redirects me to https://bug942406.bugzilla.mozilla.org/attachment.cgi?id=8337325 , where the attachment is supposed to be (and I am supposed not to be logged in). 3. But the attachment was removed, it is not there. I see a bmo page saying so. The page's appearance shows that I am not logged in. 4. That bmo page contains "Log in" and similar links, which all lead to pages at the main domain in the end, but some apparently through the attachment domain. * Maybe it should not redirect at step 2 if there is no useful destination? Does that help anything, considering that you go there through the main domain? * bug 532518 seems similar.