There isn't a way of making sure they revert back to rebel control as far as we know. Those provinces generally have parthia set as their faction_creator, so that the type of buildings they will get will be of an eastern sort and parthia is a better choice for them than sarmatia or yuezhi. This situation will get better with future builds hopefully, but we don't have a way of making them just turn rebel for certain. Sometimes that happens (witness seleukid province losses), but sometimes it doesn't and they have to 'flip' to a faction, and we are stuck with this problem.