Overview of the CI issue

At the build step, we get:

ninja: build stopped: subcommand failed.
'#' is not recognized as an internal or external command,
operable program or batch file.

but it seems that the step of the CI job happily reports an exit code of zero, so it continues to the next one. Unfortunately, it indefinitely hangs at "Run installer and launch .hoc association test", and will keep doing nothing until GitHub stops it due to reaching the time limit.

Expected result/behavior

The CI job should crash loud and hard so a developer is not puzzled why the job hangs.