I’m having the same problem with the “go to last post” function. I logged out, closed the browser, came back and logged back in — same issue.
This “last post” thing is a link that appears next to the name of the person who made the last post in a thread. The link looks like a small green button. When you click that, it’s supposed to take you to the last post in the thread. Instead (right now) it just takes you to the first page of the thread.