Actor/object Position WS won't work

I want to have a randomness in my shader, so with a Actor position in a mask, i will have a different shade grey every time i put a new mesh. But it wont work. If a create a new scene, it will work perfectly, but in that one, it’s just not working

would it be a reason why?

The Object orientation work but not the actor and not the object position ws either…

I have exactly the same problem… it works only the orientation, not the position… wich is a EPIC fail for Epic Games call it object “POSITION”… unless there´s something I don´t understand.