Rooms will always sync with the last phase. Rooms can only exist in a single phase.
If an item is created in a phase the room must exist in that phase or in a previously created phase in order to sync with dRofus items in rooms.
If an item is created in a later phase, It will not show up in the room because it is not in the bounding box geometry of the room. The phase the item is created in has to match or exist before the room in which it was created in.