Comment 1 for bug 1807194

This bug is particularly annoying because every time you submit and it tells you your username is taken, you have to type your password again twice.

The browser has not yet saved the password, so it's quite likely that the 4th or 5th time around when you're writing the password a 10th time, you'll write it differently. Then later on won't be able to log in because you're trying to log in with the password you typed the first time.