When you bump up a thread to go to the top of a forum, the date on which the last post was made changes, so if for example I posted this at 11:52 (GMT), then someone bumped it up 30 minutes later, the "last post" column would read "Today 12:22 PM by pwaring".

Is the system supposed to work like this or is it a bug? It's slightly confusing because the last post could have been ages ago, but it looks like it was only a few minutes ago if someone has bumped up the thread.