I have an iPad Mini 3 and iPhone 6 Plus. It seems that when I made an update in the iPhone the changes are not reflected in the iPad and vice versa. This applies even to Apple own app. For example, with the Reminder app: 1). I receive a Reminder alert (notification and badge) on my iPhone. I opened the Reminder app to acknowledge and delete the reminder. Alert is removed and so is app badge. 2). After an hour or so, in my iPad, the notification and the app badge still show the old Reminder alert. When I open the Reminder app in the iPad, I can see the old reminder, but within 0.5 seconds it's gone (since I delete it in no. 1 above). In both cases, the Reminder app stay in the background (I use this app a lot). Same goes with pretty much all the app that have notification and badge, whether it's 3rd party or Apple's own.