Aha, it looks like the pipeline steps remember what the current git revision was when they last ran, so the cloned steps get that rev. That kind of makes sense, but it's also annoying.

Is there any way to tell pipeline steps to get the latest HEAD revision from the repo when they run?

Thanks, I'll try that. But it seems to be doing what I expect, now. If I make changes to a step (task), I have to run it once to register that version of the task in the ClearML DB, and the pipeline pulls the rev that was current when that step was registered.

Clarification -- Task.get_task fails with the following:
clearml.Task - DEBUG - Failed reloading task 22304c030bd30b7a58889b7d5ad7a560: Action failed <400/101: tasks.get_by_id/v1.0 (Invalid task id: ids=(22304c030bd30b7a58889b7d5ad7a560))> (task=22304c030bd30b7a58889b7d5ad7a560)

So it's not that they aren't found, exactly -- it's that the task couldn't be reloaded.