As mentioned, there was a slight buggette but it has been fixed. The problem only showed up with certain browsers and not others. Running a thread/post count update takes a lot of time and is not something that is done very often so the problem may still appear until the next thread/post count update is run.
Clicking on the "last page" link should take you to the last page even if the numbers don't add up properly so please use this for the time being.