LiveActivityIntent call perfrom inconsistently

When I set Alarm with fixed schedule(Alarm.Schedule.fixed(date)) LiveActivityIntent just work inconsistently

it sometimes call perfrom but cannot call other's such as NotificationCenter.default.post

it just work fine with relativeSchedule but not for fixed schedule i want to know why it happen

tested code is under below

struct StopIntent: LiveActivityIntent { static var supportedModes: IntentModes = [.foreground(.immediate)]

func perform() throws -> some IntentResult {

    guard let id = UUID(uuidString: alarmID) else {
        NotificationCenter.default.post(name: .Alarm.stoped, object: alarmDataString)
        throw TestAlarmManager._Error.badAlarmID
    }
    Task { @MainActor in
        try TestAlarmManager.shared.stopAlarm(id)
        NotificationCenter.default.post(name: .Alarm.stoped, object: alarmDataString)
    }
    return .result()
}

static var title: LocalizedStringResource = "Stop"
static var description = IntentDescription("Stop an alert")

@Parameter(title: "alarmID")
var alarmID: String

@Parameter(title: "alarmDataString")
var alarmDataString: String

init(alarmID: UUID, alarmDataString: String) {
    self.alarmID = alarmID.uuidString
    self.alarmDataString = alarmDataString
}

init() {
    self.alarmID = ""
    self.alarmDataString = ""
}

}

I also setted supportedModes to [.foreground(.immediate)]

LiveActivityIntent call perfrom inconsistently
 
 
Q