I think i've narrowed this down to the ssh connection approach.

regarding the container that runs the pipeline:

• when I made it stop using autossh tunnels and instead put it on the same machine as the clearml server + used docker network host mode, suddenly the problematic pipeline started completing.
  it's just so odd that the pipeline controller task is the only one with an issue. the modeling / data-creation tasks really all seem to complete consistently just fine.

so yeah, best guess now is that its unrelated to clearml verison but rather to the connectivity of the pipeline controller task to the api server.

when I run this pipeline controller locally (also using the same ssh tunnel approach for comms), the pipeline completes just fine. so it's something specific about how its working inside the container vs on my machine, it seems.