Have you recompiled the project?
Do standard physics work(falling boxes and such)
Does this only happen in this project?
Have you set breakpoints in the tick function or other such to ensure that actor is getting updates?
Do BP’s still work?
Edit: What happens if you just run this as the server without clients
I always see problems like this when I’m overriding a method and forget to call Super. It’s possible they moved code into base class methods between engine versions and if your not calling those methods stuff like this happens.
Probably a long shot but just a thought on what to check.
I think its one of those with great power comes great responsibility things when using c++ in unreal. They give you full access to the api, but the downside is if you dont follow best practices it very may well come back to bite you when they change the code in the class hierarchy. I’m not sure if there is a design pattern they could follow to solve issues like this throughout the api.