$MACHINE_DOMAIN$ no longer expanded for HOST

Quite a lot of my hostnames for sessions are defined as:
$NAME$.$MACHINE_DOMAIN$

This used to pickup the hostname from the session name field, and the domain from the asset domain field.

Now I just get the following for the host:
hostname.$MACHINE_DOMAIN$

Eg for a session with the name "hostA" and the asset domain field "mydomain.ab" I would expect:
hostA.mydomain.ab

But I get:
hostA.$MACHINE_DOMAIN$

This used to work until one of the last two updates as I've got it scattered all through entries in my datasource.

Currently broken on version 2022.1.12.0