Had trouble getting the system started with docker-compose with the dev overlay because I kept getting an error like Error: Cannot find module .... bcrypt.

This seemed to have been caused by some build directory corruption, and was fixed by the suggestion here of running npm rebuild. Of course, this had to be done from within the polis-server container, so the trick is to get the system running, then run docker ps to find the process id, then use that in the command docker exec -it xxxxxxxx /bin/sh to get a shell, from which npm rebuild can be executed.

Any additional context which might be relevant?

I've had similar problems with primordials in the past which might have been fixed by doing this.

I wish there was a way to get fresh builds every time (for sure), but this might have to do with the image mapping (as a dev convenience), combined with some failure of npm to do the right thing.