RSS bug: “page not found” error in WordPress rss feed

There seems to be a bug in WordPress 3.0’s production of RSS feeds. I tested on two different browsers and with two different wordpress rss feeds:
for posts, the one found at
http://www.foobar.com/feed
and for comments, the one found at
http://www.foobar.com/comments/feed

There are these apparent bugs, or at least undesirable behaviors:
1. sometimes if you delete (permanently) all comments that are in the current feed from your wordpress blog, you get an error page back, complaining of “deletion error” (though the comments are in fact deleted).
2. you get 404 errors from the wordpress feed if you delete all the most recent posts in the feed (or the most recent comments for the comment feed). i.e. if you go to http://www.foobar.com/feed you get a 404 error. This 404 error is corrected by publishing a new post or comment. I was told by the author of the “fd feedburner” plugin that creating the new post worked around the bug by causing WordPress to reset the feed cache expiration so that the page could actually load.

Thanks for your help.