This may be a new bug. May have happened in earlier on. But now you can't access the feeds for manga entries. When you click 'SEE ALL ACTIVITY' at the bottom of a manga entry it redirects you and "Page Not Found" is the result.
Suzuka Manga | Anime-Planet
Kimi no Iru Machi Manga | Anime-Planet
Profile, Anime, Character, People and Studio links re-direct properly. This is the only one that I've found issues with.
Other Info: I use Firefox (most updated version) and I've already switched my time zone and logged out and back in.