It is interesting what is the true version of openstack-base (openstack base | Juju) In description says Stein, but when I look into a bundle.yaml file it shows me that source: cloud:bionic-train.
Moreover, when I last time installed openstack-base Stein bundle I have not seen placement charm. When I take a look into placement charm (placement | Juju) it says
“This charm provides the Placement service for an OpenStack Cloud.
OpenStack Train or later is required”
So what is the real version of openstack-base?