Earlier quoted context omitted.
Deterministic to a fault unless you mix Windows and Linux. https://github.com/yarnpkg/berry/issues/6105
As mentioned in the issue you link the problem comes from third-party packages with non-deterministic build scripts in git dependencies, or files on disk being actually different (although I guess we could at least try to normalize crlf, but as you can guess it will break someone ).
Yes, but those are third party dependencies that Yarn relies on.