I'm suddenly having the same trouble. When I hit my favorites that formerly sent me directly to the forum body, I now go to the home page. I then must click on "forum", and then on "registered users sign in". It then takes me to the forum without actually signing in.
I have no idea why this has happened, but only on one computer. Probably a result of some unwanted "up-grade".
I guess I'm just spending too much time here and this is a hint from above...
Once you are on the discussion forum page, add it to your favorite list. Overwrite any previous versions also. Enable the cookies and you'll be able to jump back and forth without having to log in every time.