For whatever reason I did not have to add the synchronizer for the pressure plate to be consistent between the clients. It is bad when it is not working and you don’t know why. But it is even worse when it works and you don’t know why. 
So the reason was simply because I skipped making sure only the server updates the state.
Then basically both the clients are updating the state independently of each other. Probably fine for things that that does not effect the mechanics of the game. For other things I can see how it could lead to bugs if consistency is not guaranteed.