I just tried to fix a mistake from sansar not copy scene when you link it to a new experience when it's already on old one. Hope there's not to much screwup now, besides things are already buggy broken.
The problem is that you sometimes cannot link a scene to existing experience. because it's not build. Ok not the first time this happens. Just build it in edit mode.
Problem. You cannot build a scene if it's not linked to some experience. But what if people not have any experience free ?
Let users build experience without the requirement of linmking it to a new scene ! Or wipe old scene first.