Flutter IOS, OneSignal app. I have the same problem.Although I am sure the phone, ios, gets the notification, the app never invoques or runs the app delegate function attached, so no action can be taken. Is notification handled somewhere else? Please help.
override func application(
_ application: UIApplication,
didReceiveRemoteNotification userInfo: [AnyHashable: Any],
fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult)