A long time ago (#751392) a patch was added to systemd to make it
create a tmpfs on /run/lock/ before starting any units, in order to
deal with some debianisms and hysterical raisins. This patch was never
accepted upstream.
I am now doing spring cleaning, and this patch will be dropped, in
favour of a standard early boot mount unit.

This means any service potentially using /run/lock and running before
sysinit.target (ie: DefaultDependencies=no) needs an explicit ordering
statement to avoid the tmpfs being created on top of them while already
running. This can be achieved with a simple drop-in.

A patch is available as a MR on Salsa:

https://salsa.debian.org/lvm-team/lvm2/-/merge_requests/14

I will upload a new version of systemd with run-lock.mount sometimes
next week, but there's no need to wait as ordering is simply ignored if
the referenced unit doesn't exist.