I updated my primary email in GitHub, and after that, when I tried to log in to Coder using GitHub, Coder created a new username for me with username old_user_name_SOME_RANDOM_STRING with the new email address. I got locked out of my old account.
Related #10726, #4618

See how a new user account is created for me after changing the email. Both are GitHub accounts.

Steps to reproduce:

1. Go to https://github.com/settings/emails and chnage your primary email
2. Logout and login to Coder