devcontainers/ci build fails, without error message

[vorburger]

This GitHub Action build which is from this PR where I'm introducing the action from this project fails strangely:

There is no failure error message (that I can tell), but it seems to just stop half way. (Note also how the "yellow dot" is still "spinning", but that test-devcontainer job has a red failure.)

I'm only see this in the job that uses this action. Everything works fine for other build jobs with other actions.

I don't suppose you have ANY idea what's going on here? What could be causing this?