Reinstall sets existing users to 'system user' and removes them from login screen

[throttlemeister]

How did you upgrade to 21.10? (Fresh install / Upgrade)
Fresh install

Issue/Bug Description:
If you do a reinstall of Pop!_OS 21.10 from recovery, which I needed to after botching something up, I found out that existing users on the system are labeled as 'system user' and are no longer visible on the GDM login screen. Also, after the reinstall, the Gnome initial setup is initiated and wants to add a new user, even though a user is already present. This cannot be bypassed. Only by adding a user you can log in, then log out, log back in as your original user and remove the new user. The original user though, remains unlisted at the log in screen, so you now have to type in both username and password.

Steps to reproduce (if you know):
See above

Expected behavior:
User is present on the sytem, and login prompt is shown for the original user. No initial setup is being performed.

Note
Existing user can be added to the login screen by navigating to /usr/lib/accountsservice and removing the file of that user. This does however not prevent the issue.

[LesleyLai]

I met the same issue. Though what I needed to do was to edit /var/lib/AccountsService/users/<username>