Geofence alerts/local notifications not waking up locked phone when triggered - ios

Question

I'm making an app that used circular regions for geofences. When the phone is active or the app is open, the geofence notifications are working fine in both simulator and device (iPhone 6 running 10.3.1).
In the simulator it works fine; When the user enters a region, it wakes up, makes a sound and shows an alert on the lock screen.
On the phone, the "didEnterRegion" delegate calls are made when entering the region (I log some messages) but the phone is not making an alert and waking up. When I push the home button once, I can see the alert on the lock screen, but I want it to wake up and show the alert instantly - like when I get a message. It works in the simulator, so I wonder what could be wrong? It has worked for me a few times, where the alert was shown on both the phone and my watch, but 95% of the time it's not working - the notifications are generated but only visible if I manually wake up the phone.
How to fix this?
Here's the code I use for creating the local notification:
// https://blog.codecentric.de/en/2016/11/setup-ios-10-local-notification/
let location = CLLocation(latitude: item.coordinate.latitude, longitude: item.coordinate.longitude)
GeoTools.decodePosition(location: location) {
(address, city) in
let content = UNMutableNotificationContent()
content.title = "Camera nearby!"
content.subtitle = item.id
content.body = "\(address), \(city)"
content.categoryIdentifier = Constants.notificationCategoryId
content.sound = UNNotificationSound.default()
content.threadIdentifier = item.id
// FIXME make action for clicking notification
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 0.001, repeats: false) // FIXME HACK
let request = UNNotificationRequest(identifier: "camNotification", content: content, trigger: trigger)
let unc = UNUserNotificationCenter.current()
unc.removeAllPendingNotificationRequests()
unc.add(request, withCompletionHandler: { (error) in
if let error = error {
print(error)
}
else {
print("completed")
}
})
}

Answer 1

Here is some code that I just verified wakes the device when notification is presented:
let message = "CLRegion event"
// Show an alert if application is active:
if UIApplication.shared.applicationState == .active {
if let viewController = UIApplication.shared.keyWindow?.rootViewController {
showSimpleAlertWithTitle(nil, message: message, viewController: viewController)
}
}
else {
// Otherwise app is in background, present a local notification:
let content = UNMutableNotificationContent()
content.body = message
content.sound = UNNotificationSound.default()
content.categoryIdentifier = "message"
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 1.0, repeats: false)
let request = UNNotificationRequest(identifier: "com.foobar", content: content, trigger: trigger)
UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
}
Really the only diff is that I don't call removeAllPendingNotifications() so if you must remove notifications I wonder if removePendingNotificationRequests(withIdentifiers identifiers: [String]) might be more precise?