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?
HTH
Edit: What happens if you just run this as the server without clients
I have checked every Class Default property, every option in the MovementComponent and all the rest.
I compared those property values between 4.10 and 4.12… apparently they’re exactly the same.
The actor (which is a grenade), though, works perfectly. It explodes after a certain ammount of time, as it is supposed to.
The only thing it doesn’t want to do, is move!
For the rest, everything works.
Even my Rockets work and move properly!* (Grenade and Rocket are two child-classes of one base class)*
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.