I frequently find that the number of items showing as unread for a feed in the left column does not match the number showing as unread in the right column. I'm not referring to when that pink message pops up in the upper right telling me an error occurred with the server. I mean that I can go down the items, opening each with the up or down arrows, even reading each one, and the feed list at the left tells me the number is higher than the actual unread count (sometimes it does not seem to have 'subtracted' any even though all the items have been read and there should be none shown as unread.

When I click again on the feed name in the left column, sometimes the right shows nothing to read while the left gives some number to read. And sometimes the items I already read reappear on the right, as if they were new.

I don't know what other info I can give you--it doesn't usually happen but it is too frequent a problem to be not irritating. The most frequent feed that this happens with is Slickideals, maybe because it is very active, but it happens from time to time with most (all?) of my feeds.