Another ones of those ran out of battery episodes. And: NO BUG!
All alarms there. Also, jolla-usersetup does not show up as failed.
My conclusion is that there is is indeed a race condition in systemd services. And it’s causing /home not being mounted at the right time.
Because looking at the script that’s run by jolla-usersetup, no home is the only thing I can see that would cause that to fail.