Comment 7 for bug 2000407

Glad to hear that you fixed your specific issue and thanks a lot for sharing those steps! I couldn't however reproduce the issue starting from a clear Lunar LXD container:

  lxc launch ubuntu-daily:lunar paride-l
  lxc exec paride-l bash

I executed the commands you provided in order and in the the /etc/nsswitch.conf has:

passwd: files systemd sss
group: files systemd sss
shadow: files systemd sss
gshadow: files systemd

No 'ldap' entry for 'passwd'. Could it be that some step is missing?