I also ran into this bug today.

When you try to sign up there is no information about password size.  If your password is too short, you get an error message after you submit.  No problem.  But then when you go back to set a longer password and resubmit it fails saying that you already registered XX seconds ago.

It could be useful to both put the password restriction information on the registration page, and also not invoke the "already registered" if the registration failed.  First part is probably really easy, second part not as much.