DanDare noted a spam report and wanted to deal with it, and while it's closed and marked as spam, there's still a URL extant, and we see no way to remove it.
The bug is #257805. The initial thought is that if something is already automatically marking the bug title and comments as spam, that same thing might also remove submitted URLs and presumably attachments.
*** Bug 258250 has been marked as a duplicate of this bug. ***