Facebook Analytics Push on iOS only works occasionally - ios

Question

I have been battling with this for a while now but I've finally succumbed to submitting a question to see if anyone else has had an issue.
Essentially I'm trying to use the Facebook Analytics push service and only seem to be receiving push notifications some of the time. I've been intercepting the API calls using charles proxy to ensure that push tokens are being sent correctly by the Facebook SDK and events are being logged as expected. From this perspective everything is fine.
Next I use the 'Push campaign setup verification' on the settings page to try and send push and in-app push tests, and these also work fine (cards are displayed correctly on the devices etc.) on the 3 test devices I'm using.
The problem arrises when trying to create a campaign to send pushes to a certain segment of the devices. The first device I tried with worked with no issues at all, but then subsequent devices (with no changes to the codebase at all) wouldn't receive any pushes from any campaigns that I set up. My target audience is 'Device OS is iOS' so I would expect that all iOS devices would receive the push from the campaign. This seemed a bit odd, so I deleted the app off all the devices and rebuilt them again (ensuring that the test push worked on all devices) and setup the campaign again, but this time even the first device no longer worked. In the events debugger I get a 'Push Notification Error' and an error_message of 'InvalidDeviceOS' which makes no sense at all.
I've been going back and fourth with this for a few hours now with no success. I can see the tokens being sent to Facebook, and I can see the events being logged in the event debugger, I can use the push test service in settings and all devices receive pushes without an issue, but as soon as I try to use a campaign I get nothing.
For completion purposes here are the snippets of code I'm using:
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// ...
application.registerUserNotificationSettings(UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound], categories: nil))
// ...
}
func application(application: UIApplication, didRegisterUserNotificationSettings settings: UIUserNotificationSettings) {
UIApplication.sharedApplication().registerForRemoteNotifications()
}
func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
FBSDKAppEvents.setPushNotificationsDeviceToken(deviceToken)
}
Finally here is the events debugger after opening a fresh install on 3 different devices (see the first launch events, 2 app launches have ID's and 1 doesn't as it's not logged in yet).
Any help with this would be great, thanks.
UPDATE: I created a brand new app and a brand new Facebook analytics instance, new push certificates etc. Initially I started receiving pushes from campaigns, but once I deleted and reinstalled the app the campaign messaging started to fail again. I then installed it onto a different device and cloned the existing campaign and tried again. This then resulted in the original device getting the push but the new device didn't... the mind boggles!
Now I don't know whats going on. On the face of it the Facebook service seems to get flaky once a push error comes back from APNS, but it's really difficult to prove that assumption since the error reporting in the Event Debugger is next to useless.
Again for completeness here is the code from the new app:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
application.registerUserNotificationSettings(UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil))
return true
}
func applicationDidBecomeActive(_ application: UIApplication) {
FBSDKAppEvents.activateApp()
}
// MARK: Notification Methods
func application(_ application: UIApplication, didRegister notificationSettings: UIUserNotificationSettings) {
application.registerForRemoteNotifications()
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
FBSDKAppEvents.setPushNotificationsDeviceToken(deviceToken)
FBSDKAppEvents.setUserID(NSUUID().uuidString)
var token: String = ""
for i in 0 ..< deviceToken.count {
token += String(format: "%02.2hhx", deviceToken[i] as CVarArg)
}
print("Token: \(token)")
}
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
if FBNotificationsManager.shared().canPresentPushCard(fromRemoteNotificationPayload: userInfo) {
FBNotificationsManager.shared().presentPushCard(forRemoteNotificationPayload: userInfo, from: nil, completion: nil)
} else {
print("Unknown Payload")
}
completionHandler(.newData)
}
UPDATE 2: After hours of experimenting and digging we came across this bug report on Facebook's support pages which seems to confirm this is not an isolated issue: https://developers.facebook.com/bugs/118059088679219/