I'm pretty sure generated RSS feeds from Moodle 2.0 (on Moodle.org) are no longer inheriting the correct title from the post.
See the attached screenshot from my google reader feed, the feeds at the bottom are Pre 2.0 upgrade - they have Re: in responses. The later ones are from Moodle 2.0 upgrade and are missing the Re: bit.
Looking at the posts in question: http://moodle.org/mod/forum/discuss.php?d=159340
This is because the rss isn't being generated with the correct title..