GKTurnBasedMatch push notifications are very inconsistent

Question

I'm testing a turn based game between two devices. As far as I understand, sending a turn with [GKTurnBasedMatch endTurnWithNextParticipants:], for example, should automatically push a game center notification to the opponent. Sometimes, this works just as expected: the turn is sent and right away a banner notification shows up on the other device. All is well.

What is baffling me is that other times, even though the turn itself is sent properly (I can tell because when the opponent refreshes the matches, the match is up-to-date), there's no push notification coming in.

Are there any holes in my understanding here? If I'm understanding correctly, the inconsistent notifications shouldn't have anything to do with my code, because the issue here isn't how I handle notifications, it's that there is no notification at all. In other words, [handleTurnEventForMatch:] (aGKTurnBasedEventHandlerDelegate method) doesn't have anything to do with it (I don't think) because if no notification is being received, it's never going to be called anyway.

So, I'm just wondering if anyone has had any experience with this. Is it possible that this is due to something in my code? Or, is it possible that the Game Center sandbox is responsible for the inconsistencies, and there's nothing I can do about it?

Any thoughts or ideas would be much appreciated.

Answer 1

It is an issue with GameCenter's sandbox mode. In order for your device to enter sandbox mode you have to open/run your app and authenticate game center. If you say, open a different (published) game after your game is open it will leave sandbox mode and and go back to regular game center mode.

Even if your game is running in the background, as long as it is the last game-center enabled game opened you should get the push notifications as normal. But if you open the game, and then kill the process, you will no longer be in sandbox mode and will not receive the push notifications.