I’ve done some testing and made sure the database wasn’t corrupt.
I have been able to replicate one thing in the list of issues so far.
If you are in a protected part of the forum or on a protected page and log out: once logout is complete the site tries to forward you back to the page you logged out from, since this page is protected you will be forwarded on to the signup page.
I’ve tried all the ways I can think of to replicate the login issue. For those of you having problems, please post what page you are trying to start from. The homepage or somewhere else?
I suspect some folks may be having issues with cookies and forwards… but I can’t prove that yet.