I think he means his link, searching the text doesn't show "exit code," though maybe it is worded differently.

she did not, the exit code story is a different thing, though one I told on HN before. basically i spent half a year or so with writing infra and autoscaling for action runners on GCP, and there's absolutely nothing there i'm proud of. the pieces just didn't fit together. and weirdly enough, the majority of the blame isn't even with GCP and their broken image snappotting, slow provisioning times and asinine API design.

The linked issue is not about random exit codes though? And also doesn't really seem to support his assertion that the maintainers don't know how it works, but I'll admit I'm not very familiar with GitHub Actions.