Being redirected to login screen upon editing settings

Have you checked your browser?
I am seeing the same problem with firefox 5.0, but not with IE9 or opera 11.05.
When I login, I have a successful login, but i redirect back to the login page, the redirect to the dashboard doesn’t work. A workaround is to visit the site, where I am logged in, because the admin bar appears and then click edit page to get into the backend.

This is reproducible across all of my WP sites. They are all on the same webhost, which may be related, or a red herring.

It looks like Firefox is at fault here, at first pass, but may be wordpress. I have updated all my blogs so cannot check in a later version.

This page seems to indicate that firefox 5 caches pages differently. It may be that wordpress has to amend the redirect method to cope.

SS