There is something wrong with cargo-near-build, it seems. There is a project where it used to work (cargo-near-build there is 0.3.0, but neither it works with that old version nor it works after I upgraded everything cargo-near, cargo-near-build, and the build image):

git clone https://github.com/near-devhub/neardevhub-treasury-dashboard
cd neardevhub-treasury-dashboard
cargo near build reproducible-wasm

I tested it on MacOS and Ubuntu, with old cargo-near 0.10.1 + cargo-near-build 0.3.0 and new cargo-near 0.13.2 + cargo-near-build 0.4.2, but it just fails and I cannot figure out what is wrong. Compiling the child contract on its own works just fine.

Here is the branch with the updated cargo-near versions: refactor/upgraded-reproducible-config