I tested with three accounts, now on three computers. With netscape, Safari, IE 8, IE7, Chrome, and Firefox. The only time it does it to me is if I click more than once on the thread (I did that a couple times.)
I did make a change, hence the request to test. I even went to the same threads in different ways. I was able to duplicate it, but only when I clicked more than once on the thread (the server was slow and it annoyed me, I clicked a second time.) In those instances it would take me to the last post, or to the next page if there was more than one page.