Thanks for the reply. In our case it isn't wheel caching: we don't deploy a wheel. Our tasks are plain Python script tasks, deployed via a Databricks Asset Bundle directly into the workspace, e.g. /Workspace/Users/<user-id>/.bundle/project/Default/production/files/src/...
So there's no pip install and  we've also already redeployed several times with no change.

The failing imports are for modules/functions inside the bundle's own source tree. It's intermittent and moves around: a task fails with "No module named ..." / "cannot import name ...", the next run passes it but fails another task the same way. That looks like files not being reliably visible at import time 🤔

I also noticed a recent maintenance update for 17.3 LTS, so I'm wondering if this could be related.

Same issue seems to be reported here by someone else (also two days ago), and I've added a message too.