If I click on the link "Unanswered posts" I get a page of results including several posts to which there have been >0 "Replies". Surely a reply is an answer to a post? If not, how does ETO define an 'answer'?
I have a theory that maybe the posts with non-zero replies were un-answered when you looked at "unanswered posts" at an earlier time, and they are now stuck in your unanswered posts list.
To test my theory, I had a look at my "Un-Answered Posts" before the previous reply.
Your post was there, un-answered.
I replied and then went away from ETO to a couple of other sites, came back to ETO and looked at my "Unanswered posts" again, and there was your post still at the top of the list but showing my one reply.
Hmm. Interesting, Jim. I'd assumed that the unanswered list was global, but from your experiment it seems forum members have individual lists (presumably stored as cookies?). Can't see any advantage in that. IMO a global list would be more helpful.
I have noticed this too. I believe it maybe to do with indexing posts. Since it runs off the search engine for this site it can take some times to update the index to reflect recent posts.
Its somewhat of a guess and I may need to look into it further..