🤷🏽♂️ I'm afraid that you ignored the remarks where I've mentioned that no production system should be upgraded to V4 until I say that is safe to do it. This is mentioned in V4 FAQ.
If you found a bug it will be nice if you can report it accordingly. If you aren't into debug or using beta software then go back to V3 until I release the production grade V4.0.0 release.