Form feeds return a 404 when the RSS feed link is clicked.
It appears that the 404 is returned if any request parameters are sent. And the feed contains some url params. I.e.,
this works: http://forums.demigodthegame.com/369318
this doesn't: http://forums.demigodthegame.com/369318?x
and this is the url from the feed: http://forums.demigodthegame.com/369318?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Stardock%2F25%2Frecent+%28Demigod+Forums+%C2%BB+RSS+Feed+%C2%BB+Recent+Forum+Posts%29&utm_content=Google+Reader
This is the error message I get:
Sorry if this has already been noted but I couldn't find it after a quick search.