Comment # 6 on bug 1110456 from Thomas Blume

(In reply to Thorsten Kukuk from comment #5)
> (In reply to Thomas Blume from comment #4)
> > So, maybe apparmor needs to be reconfigured (on my reference machine there
> > is no apparmor installed).
> > Can I disable apparmarmor and reboot your machine to double check?
> 
> Yes

I was wrong, this has nothing to do with apparmor.
The configuration issue is in:

/etc/systemd/journald.conf

that defaults to:

#ForwardToSyslog=no

as soon as I set:

ForwardToSyslog=yes

and restart journald, it works correctly.
That matches the documentation in the journald.conf manpage.
On SLES it defaults to ForwardToSyslog=yes, that's why it works there out of
the box.

The interesting question is why it worked on my reference Tumbleweed machine,
even though it also defaults to ForwardToSyslog=no.
But that might not be of interest for you.