UNNotification не работает, когда дата создается из NSTimeInterval

Question

Следующий код работает (iOS 10.3.3). Кнопка HOME была нажата после триггера, чтобы перевести устройство в фоновый режим. В назначенное время с системным звуком по умолчанию сработало уведомление. Обратите внимание, что текущая дата используется в триггере.

    -(UNNotificationRequest *)triggerNotifications: (NSString *)identifier : (NSTimeInterval) interval{
    // Note: identifier must be unique or else each new request causes all others to be cancelled.
    UNUserNotificationCenter* center = [UNUserNotificationCenter currentNotificationCenter];
    UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];
    content.title = NSLocalizedString(@"Timer expired", nil);
    content.body = NSLocalizedString(@"Touch to continue", nil);
    content.sound = [UNNotificationSound defaultSound];
    content.categoryIdentifier = @"com.nelsoncapes.localNotification";
    NSDate *today = [NSDate date];
   // NSDate *fireDate = [today dateByAddingTimeInterval:interval];
    // first extract the various components of the date
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSInteger hour = [calendar component:NSCalendarUnitHour fromDate:today];
    NSInteger minute = [calendar component:NSCalendarUnitMinute fromDate:today];
    NSInteger second = [calendar component:NSCalendarUnitSecond fromDate:today];
    //then make new NSDateComponents to pass to the trigger
    NSDateComponents *components = [[NSDateComponents alloc]init];
    components.hour = hour;
    components.minute = minute + 1;
    components.second = second;
    // construct a calendarnotification trigger and add it to the system
    UNCalendarNotificationTrigger *trigger = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:components repeats:NO];
    UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier: identifier content:content trigger:trigger];
    NSLog(@"request: %@", request);
    [center addNotificationRequest:request withCompletionHandler:nil];
    return request;
}

Однако небольшое изменение кода (путем передачи NSTimeInterval методу triggerNotifications) НЕ работает. Обратите внимание, что fireDate создается из переданного NSTimeInterval:

    -(UNNotificationRequest *)triggerNotifications: (NSString *)identifier : (NSTimeInterval) interval{
    // Note: identifier must be unique or else each new request causes all others to be cancelled.
    NSLog(@"interval: %f", interval);
    UNUserNotificationCenter* center = [UNUserNotificationCenter currentNotificationCenter];
    UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];
    content.title = NSLocalizedString(@"Timer expired", nil);
    content.body = NSLocalizedString(@"Touch to continue", nil);
    content.sound = [UNNotificationSound defaultSound];
    content.categoryIdentifier = @"com.nelsoncapes.localNotification";
    NSDate *today = [NSDate date];
    NSDate *fireDate = [today dateByAddingTimeInterval:interval];
    // first extract the various components of the date
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSInteger hour = [calendar component:NSCalendarUnitHour fromDate:fireDate];
    NSInteger minute = [calendar component:NSCalendarUnitMinute fromDate:fireDate];
    NSInteger second = [calendar component:NSCalendarUnitSecond fromDate:fireDate];
    //then make new NSDateComponents to pass to the trigger
    NSDateComponents *components = [[NSDateComponents alloc]init];
    components.hour = hour;
    components.minute = minute;
    components.second = second;
    // construct a calendarnotification trigger and add it to the system
    UNCalendarNotificationTrigger *trigger = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:components repeats:NO];
    UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier: identifier content:content trigger:trigger];
    NSLog(@"request: %@", request);
    [center addNotificationRequest:request withCompletionHandler:nil];
    return request;
}

Это интервал, записанный NSLog (240 секунд) и последующим запросом UNNotificationRequest:

    Chime2[2548:1304491] interval: 240.000000
2017-11-04 14:26:39.154548-0500 Hourly Chime2[2548:1304491] request: <UNNotificationRequest: 0x14ec72d0; identifier: AETEwJM9xA1azuQ4pDja, content: <UNNotificationContent: 0x14ec6f80; title: Timer expired, subtitle: (null), body: Touch to continue, categoryIdentifier: com.nelsoncapes.localNotification, launchImageName: , peopleIdentifiers: (
), threadIdentifier: , attachments: (
), badge: (null), sound: <UNNotificationSound: 0x14ec7120>, hasDefaultAction: YES, defaultActionTitle: (null), shouldAddToNotificationsList: YES, shouldAlwaysAlertWhileAppIsForeground: NO, shouldLockDevice: NO, shouldPauseMedia: NO, isSnoozeable: NO, fromSnooze: NO, darwinNotificationName: (null), darwinSnoozedNotificationName: (null), trigger: <UNCalendarNotificationTrigger: 0x14eb6cc0; dateComponents: <NSDateComponents: 0x14ed0980>
    Hour: 14
    Minute: 30
    Second: 39, repeats: NO>>

НО, установка переданного интервала в 60 секунд или 120 секунд работает.

Что здесь происходит?