Hello all, good morning!
I'm trying to deploy a VDI with Ubuntu 22.04 to our developers using view agent more recent, 2212.8.8.0-21071111.
Everything works great using vmware documentation but I'm getting an issue when tried to use SSO. If i try to login using an username that starts with digit, the login process enter in loop. I found a bug report on systemd that points to this error, but they sad that issue was solved (https://github.com/systemd/systemd/issues/15149).
auth.log:
============ user: 1234567 ============
Feb 15 09:25:38 tplvdi-ubun5 lightdm: pam_unix(lightdm:session): session opened for user 1234567(uid=1595448886) by (uid=0)
Feb 15 09:25:38 tplvdi-ubun5 lightdm: pam_systemd(lightdm:session): Failed to get user record: Invalid argument
============ user: da1234567 ============
Feb 15 09:26:00 tplvdi-ubun5 lightdm: pam_unix(lightdm:session): session opened for user da1234567(uid=1865311371) by (uid=0)
Feb 15 09:26:00 tplvdi-ubun5 systemd-logind[1225]: New session c15 of user da1234567.
Tried:
1) Using cli "login 1234567" auth without problem.
2) Use lightdm instead gdm, error persists.
3) Configure use_fully_qualified_names = True, auth works fine using "@Domain" but break Horizon SSO from web or horizon client.
4) Tried to change nsswitch.conf without success.
Config files:
nsswitch.conf
sssd.conf
krb5.conf
If someone can help, i'll very glad!!!! 
After so many minutes spent in this thread, I guess I found a solution and will post here to help someone that have this problem.
I changed the config SSOUserFormat in /etc/vmware/viewagent-custom.conf on my golden imagem template to
SSOUserFormat=[username]@[domain]
Also i've changed the sssd.conf:
After reboot, I've follow the steps to create a dektop pool and our devs success login to VDI.