For at least one feed (http://rss.slashdot.org/Slashdot/slas…), the feed seems to be “stuck” on a couple days’ worth of stories. Even though the feed lists itself as unread, and as “show unread items only”, the first story listed is “Oracle Clings To Java API Copyrights” from March 31st. It then continues with all the stories until “Soyuz Breaks Speed Record To ISS” from April 1st, at which point it picks back up with the true unread stories (if any).
My username is ‘schala’, FWIW.