Originally Posted by Alexander Turcic
That wouldn't fix anything in regard to the browsing issue your are experiencing. Essentially, your browser still thinks that the temporary upgrade page, which no longer exists, is the new page for the user CP. There is no mechanism for us to tell your browser to empty its cache of this redirect. That's why I have been trying to give you tips which worked for others but for some reason not for you.
I wonder... if you put a 301 redirect at the page you redirected to before that redirects to the userCP section of MR, would that not maybe fix things?