How many people are also seeing this? In settings, under "Mobile Data", the apps which are switched off cannot be switched on. The switch moves to the right as if they're turned on, but has no effect and when leaving and re-entering the settings page they're still turned off. This is a MASSIVE and crippling bug. I've seen one or two references to this googling, from other users of the GM, but I've restored my iPhone from the proper iOS9 release and still have this.