Not GP, but here's an example I've seen. Kubernetes files are generated by Jsonnet. It is invoked from makefiles. Makefiles are spread across different git modules. The scripts require various Go binaries. Most are installed through a command, some have to be installed manually. If the version is wrong, mysterious errors happen.

I once had a problem with the generated files so I deleted the generated directory and regenerated everything. Turns out you can't do that. The generated files are edited, and if you generate from scratch you've wiped out the manual edits.

Note that I'm not criticizing Kubernetes here. But when you have a non-simple system with some missing aspects, some people take the opportunity to make it even more complex.