Users not seeing local notifications

Some users are telling me they "never" or rarely get alerts sent by my app while in the background. I have no such problem on my phone - I get alerts frequently. I've checked every setting we can find related to background app refresh, and to notifications, but all seems in order.


My app (AirCompare) does background fetches, processes a small amount of web data, and then sends an alert. This all works fine for me and most users. In the case of the affected user, my app logging shows that alerts were requested, but the user never saw them.


Here's an example alert, one relaed to the weather:

requestIdentifier = "Tickle Weather"
content.title = "... Weather update ..."
content.subtitle = ""
content.body = "my alert text"
content.sound = nil
logSB.info("Tickle Weather alert sent at \(currentDate)")
let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval: 0.2, repeats: false)
let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: trigger)
    UNUserNotificationCenter.current().add(request)  {  (error) in
            if (error != nil){
                self.logSB.error("ERROR sending a notification at \(currentDate)")
            }  // close error conditional
      }  // close userNotification


The user's logs show that web data were fetched and processed and that the alerts are sent with no error logged. But the user sees nothing.


What are we missing?


[update] I forgot to mention: When the user crosses a geofence set within my app, that notification comes through. Occaionally one of the previously missing alerts will fire at the same time, even a day late.

Another clue:


UNUserNotificationCenter.current().add(request) does nothing for the user. Works fine on other phones.


requestIdentifier = "Tickle Weather"  
content.title = "... Weather update ..."  
content.subtitle = ""  
content.body = "my alert text"  
content.sound = nil  
logSB.info("Tickle Weather alert sent at \(currentDate)")  
let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval: 0.2, repeats: false)  
let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: trigger)  
UNUserNotificationCenter.current().add(request)  {  (error) in 
     self.logSB.debug("A notification was requested at \(currentDate)")  // DOES NOT LOG
            if (error != nil){  
                self.logSB.error("ERROR sending a notification at \(currentDate)")  
            }  // close error conditional  
      }  // close userNotification

Alright I guess I'm shouting into an empty canyon, but I'm pretty sure my problem is that background fetches are never triggered for my affected users. The alerts work fine but they normally trigger at the end of a successful fetch, and there are none. They trigger fine for my iPhone and in Simulator, but users are never seeing a fetch. Alerts triggered by crossing a geofence border work fine. But no background fetch ever gets asked for.


I'm going to doublecheck the authorization for fetches as below but I have no reason to suspect they are not enabled. In my App Delegate:


        switch UIApplication.shared.backgroundRefreshStatus {
        case .available:
            self.logSB.debug("backgroundRefreshStatus is AVAILABLE")
        case .denied:
            self.logSB.debug("backgroundRefreshStatus is DENIED")
        case .restricted:
            self.logSB.debug("backgroundRefreshStatus is RESTRICTED")
        default:
            self.logSB.debug("backgroundRefreshStatus is unknown")
        }
Users not seeing local notifications
 
 
Q