Lots of machines in cloud but only a few in docker-machine

We are currently running on 4.1.0 (I will upgrade later today) and we have the problem (since multiple versions) that docker-machine creates servers but some how fails to remember those.

I recently manually deleted about 30 servers in Hetzner cloud that weren't known to docker-machine ls (anymore?) but definitely created this way.

We are using docker-machine to spin up cloud runners for GitLab CI, so every runner has a fixed prefix and is easily recognizable.

Is there a way to sync docker-machine with hetzner cloud, so that these servers get picked up again? Or that docker-machine recognizes those unmanaged machines and removes them? This is filling our resource limits and bills as well :)

Can I provide logs (which?) to debug this? This usually stacks up over multiple weeks and does not happen on a daily basis.

Start by reproducing the buildup of Hetzner Cloud servers for docker-machine runners and compare the resources shown by docker-machine ls with the cloud account, using the fixed runner prefix. Inspect the available driver logs and determine whether the completed fix should recover unmanaged servers or reliably identify and remove them.