Cant confirm it was never the case, but its the case for at least 5 years. Dont really like that you basically have to protect the ally since they could be toxic players (and all they need is to kill their base and its over; you cannot outright kill them if they teamkill) or if they leave the game you need to have at least some sort of protection for base It also makes soloing the missions harder if you want to go for a solo run.