rpm-ostree based system, so initramfs built with no-hostonly=true
/etc/group is thus almost empty
In the boot log I see

localhost systemd-sysusers[770]: Creating group 'nobody' with GID 65534.
localhost systemd-sysusers[770]: Creating group 'users' with GID 100.
localhost systemd-sysusers[770]: Creating group 'root' with GID 999.
localhost systemd-sysusers[770]: Creating group 'dbus' with GID 81.
localhost systemd-sysusers[770]: Creating user 'dbus' (System Message Bus) with UID 81 and GID 81.

What were you trying to do that didn't work?

No idea if this actually breaks anything, but it could

What is the impact of this issue to you?

Uncertain

Please provide the package NVR for which the bug is seen:

systemd-252-46.el9_5.2.x86_64

How reproducible is this bug?:

100% with my build setup (minimal rpm-ostree based system)

Steps to reproduce

1. build an initramfs with no_hostonly=true and boot on it, look at the logs

Expected results

root group has gid 0 in initramfs (no log or creating with gid 0)

Actual results

localhost systemd-sysusers[770]: Creating group 'root' with GID 999.

Additional info

A possible fix is to backport
https://github.com/systemd/systemd/commit/49bb7fe5f88fc35b8529d7d8dfcd4c151a9aaf1a
https://github.com/systemd/systemd/commit/9361a712f85860ead532dba1468dbd3deef00e34