If this problem has been reported before, I don't remember it. Nothing about our Trac installation has changed recently that I'm aware of. In case it helps, I just updated to Trac 1.0.11.
It's unclear if the problem would be our problem and or an issue with Trac but for what it's worth, our bug tracker for
code.djangoproject.com is:
https://github.com/django/code.djangoproject.com/issuesI guess we need steps to reproduce the empty cookie.