Yeah, whatever they did in 5.1 breaks so much. My general advice is unless you need 5.1 features, stick with 5.0. It is far more robust and you wouldn’t think that would be the case but it is true. I also found with 5.1 that my pc is struggling and yet 5.0 was fine. Mostly gpu but framerate halved in 5.1
These kind of breaking changes has happened before with 4.21. That was a truly bad release and used to corrupt projects. 4.22 onwards are great. In fact, 4.26 to 4.27 also had issues.
It is best to stick with a release until at least 1 update for it has appeared. It didn’t help 4.21…