Bluetooth pairing failed if checking service supported

Question

I wrote the following code to scan nearby Bluetooth device. But I found pairing failed if calling Nus.IsSupport() in watcher.Added() function and pairing successfully without calling Nus.IsSupport() in watcher.Added() function. Do you have suggestion to fix this issue?

internal sealed class DeviceWatcher
{
    private readonly Windows.Devices.Enumeration.DeviceWatcher watcher;
    private readonly AutoResetEvent watcherStoppedEvent = new(false);
    private List<Windows.Devices.Enumeration.DeviceInformation> devices;

    public DeviceWatcher(AsqFilter filter)
    {
        watcher = Windows.Devices.Enumeration.DeviceInformation.CreateWatcher(filter.Query,
                                                                              null,
                                                                              Windows.Devices.Enumeration.DeviceInformationKind.AssociationEndpoint);

        watcher.Added += (_, info) =>
        {
            if (String.Compare(info.Name, "") == 0)
            {
                return;
            }
            
            // calling Nus.IsSupport() caused pairing failed
            devices.Add(info);
        };
        
        watcher.Removed += (_, removedDevice) =>
        {
            try
            {
                var tempDevices = new List<Windows.Devices.Enumeration.DeviceInformation>(devices);
                foreach (var device in devices)
                {
                    if (device.Id == removedDevice.Id)
                    {
                        tempDevices.Remove(device);
                    }
                }
                devices = tempDevices;
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Failed: {ex.Message}");
            }
        };

        watcher.Updated += (_, updatedDevice) =>
        {
            foreach (var device in devices.Where(device => device.Id == updatedDevice.Id))
            {
                device.Update(updatedDevice);
            }
        };
        
        watcher.Stopped += (_, _) => watcherStoppedEvent.Set();
    }

    public void Start()
    {
        Console.WriteLine("watcher start");
        devices = new();
        watcher.Start();
    }

    public IEnumerable<Windows.Devices.Enumeration.DeviceInformation> Stop()
    {
        watcher.Stop();
        var receivedSignal = watcherStoppedEvent.WaitOne(5 * 1000);
        if (!receivedSignal)
        {
            Console.WriteLine("Warning: the watcher didn't stop after 5 seconds");
        }

        return devices;
    }
}

}

Answer 1

AmBle.Bluetooth.Service