App with local notifications not appearing in Noti

Question

So I just got a complaint from a user saying they were not receiving any notifications from my app. I asked them to go into the Settings app -> Notification Center and check to see if alerts from the app were toggled on. (Banners, Badge app icon, Sounds, Show in notification center, show in lock screen)

Surprisingly, he mentioned that the app wasn't even in the list of apps in the Notification Center. This is weird because on my device, and all devices I've tested with, the app is listed under Notification Center and notifications work fine. How could this possibly happen?

Also, keep in mind that my app only uses local notifications, not push notifications.