You're missing the point. Storing translated files is caching things in git, and it is not a bad idea. It's a standard practice that saves your neck.
You either place faith on a build step working deterministically when it was not designed to work like that, or you track your generated files in your version control system.
If you decide to put faith on your ability to run deterministic builds with a potentially non-deterministic system, you waste minutes with each build regenerating files that you could very well have checked out and in the process risk sneaking in hard to track bugs. Then you need to have internationalization test steps for each localization running as part of your integration tests to verify if your build worked, which consume even more resources.
Or... you stash them in git?
You use git to track changes, regardless of where they came from. Just because you place faith in some build step to always work deterministically that does not mean you are following a good practice and everyone else around you is wrong.