Why does (correctly) setting an environment variable cause a postcreate script to fail?

[ahjulstad]

A minimal example here: ahjulstad/julia-devcontainer-feature-errror-minimimworkingexample@df76810

With the additions to the PATH, for some reason the postcreate no longer runs. Comment it out, and it works. The script itself can easily be run in a shell afterwards; so there seems to be no reason for the script to fail.

[ahjulstad]

I have filed an issue in the feature repo JuliaLang/devcontainer-features#18 but wonder if this is related to some core devcontainer functionality.