Is it possible to use --userns=auto as root while disabling user namespaces for unpriviledged users?

[dcblanik]

I use Rocky Linux 10 with selinux enforcing and have set
# echo "user.max_user_namespaces = 0" >> /etc/sysctl.d/user-ns.conf
which completely disables rootless podman. So far so good.
As root I can still use podman mostly as ususal, however, when I try to use --userns=auto I get the following error:
Error: OCI runtime error: crun: clone: No space left on device
Is this expected behaviour?