I have the same problem on my blog erecruteme, it looks to be a bug. Have you submitted a Feedback report? (I can’t talk, I didn’t).
Can you remember anything particular you did with these posts that may have caused it? I thought the phantom numbers might have been caused by working with posts in Draft mode, categorizing them, then deleting. However, as you say there are actually showing up more than once in the list.
That sounds like a bug on the backend. (I have a client who is known to double click and wound up with many dupe posts. Lots of fun tracking that one down.) I vote for the feedback method. Do make sure that you point very specificly to examples though so they don’t delete your data. :)