Until today, clicking on the time tag of the last reply shown on the Discussion Forums page linked to the last reply. As of today -- at least on my system -- it links to the start of the thread.
FWIW, clicking on the time tag of the last post on the thread page does go to the last post. It appears to be the same URL as the one on the Discussion Forums page, but they take you different places.
P.S. No, I haven't cleared cookies to see if that changes things.
They both go to the same page, but the time link will scroll you down to that post. Sometimes it takes a second or a few to actually initiate the scroll. And if your browser/computer is blocking the script that does it, that would also cause it to not work.
FWIW: When I clicked on the time tag of your post, it took me directly (and quickly) to your post as intended, so I'm thinking that it's not a blocked script. However, when I tried it again, it took me to the top of the thread. Random tries on tags from other threads take me to the top of the thread and stay there, even if I wait a couple of minutes.
At first, I couldn't replicate it and all was working fine. But I was clicking on the time, and then returning to the discussions list by clicking the menu item at the top. Then I tried going back to the list using the back button in my browser and it worked the first two times before it stopped working. Are you using the back button?
I think my usual practice is to click on the Discussion Forums link in the left-hand pane to get back to the list.