Django 1.2 session loss (Stack Overflow users fail at this question)

Hi,

I've been experiencing a massively frustrating bug whereby some users can register and use my site without a glitch and, yet, others experience a problem wherein they spontaneously lose their logged in state and are redirected to a login page (via an @login_required decorator).

A number of other people have suffered this problem (see http://stackoverflow.com/questions/1693726/problem-with-combined-authentication-login-view).

The issue that both this person and I have had is that we register, authenticate, and login a user in a single view. For most users that's fine, but for some, the subsequent request returns an Anonymous User, even though they were signed in via the register view.

It has been suggested that this is potentially a threading issue. I've also seen it suggested that it relates to the backend for caching session data.

Any thoughts?