It's a bug in the system. On my other computer, it normally shows a page from a month ago. F5 takes care of the main forums, but the group discussions are wacked, too usually showing the first thread that was posted as the one on top.
I've noticed this off and on for a while especially in some of the groups I belong to. Playing with the arrow buttons at the top usually gets me back to where I need to be, but it is a pain because they don't work in a way that seems logical to me.
