Logging in with existing cookies causes login problem

Since we're all in a bug reporting festive mood, I thought I'd join in.

I've noticed this for quite some time, basically when upgrading, moving a database from localhost to remote (or vise-versa), or when any other conflicting action happens where existing cookies won't automatically log a user into the board, if they attempt to login (and succeed) the redirect page will log them out automatically.

I have personally had this happen at least two dozen times that I can recall... and I've seen many other admins experience the same issue. I don't believe it happens as much with the end-user.

Clearing cookies ALWAYS resolves this issue, so perhaps there is a way to reset the cookies on login so that this does not happen... ?