It has been a few months since I last used the multiplayer template - but it worked fine.
It is very easy to run into trouble if you are not clear on how it works. If your peer position is getting reset, then you are probably trying to move it manually, rather than having the host move it (then on sync, the host moves it back to where it thinks it should be).
When you follow the rules, it works well, but if you try to do things like you would in a single player game you will break it very quickly!