It sometimes includes threads that I have recently answered. For example, click Unanswered Threads, post in one of them, then click Unanswered Threads again -- the thread you posted in still shows up, but this time it shows correctly that there was 1 reply. I would have expected it to not have show up any more since it has been answered.

I've noticed a similar behavior with the "Threads I've Posted in" button. It seems there is a lag in it. How long it takes to add threads seems fairly random, sometimes as much as an hour. Once added, the new posts behavior is fine. Perhaps it's some sort of cached results thing related to the DBase(s)?