I can confirm that setting UID_MIN 500 in /etc/login.defs completely fixes this problem.
My user account did not show up in lightdm, user switcher and user accounts and also was shown as Invalid UTF-8 in the panel. This now all works fine.
The user ID is 501.
I can confirm that setting UID_MIN 500 in /etc/login.defs completely fixes this problem.
My user account did not show up in lightdm, user switcher and user accounts and also was shown as Invalid UTF-8 in the panel. This now all works fine.
The user ID is 501.