when I was just on the forums, and then opening the "Settings" of my account on the top right, it has lead me to the settings page. Then I tried to go back to the forums, and I have gotten a bad request. This happens because the settings page is on a different domain, and it had to log me in again (it was done automatically though). when I used the "go back" button, it didnt actually go back to the forums, but instead some authentification/verification login link, which is only valid once. this is why I got a "bad request".
after that, I again went to the forums, clicked settings, and went back, and this time it worked. this is because at that point my browser has already saved my credentials from my previous attempt, and it wasnt necessary to go through the login process.
I have found that in general, there are WAY too many redirects involving logging in into your account. sometimes up to 5-6 different domains, that my browser needs to go through, before im finally logged in.