Exception thrown during deconnection with D435

Hi All,

I have tried to develop a C# class for multiple IntelRealSense D435 cameras.

 I tried to use a delegate function on OnDeviceChanged event, that should arise with connection/deconnection of camera. The problem is when I disconnect the camera a CallbackOnCollectedDelegate exception is thrown.

public class DepthCameraCluster<T> where T : IDisposable
    {
        #region Fields
        private static Dictionary<string, DepthCamera<T>> depthCameras;
        private static Dictionary<string, ProductInfo> availableCameras;
        private static Context context;
        
        private static bool stopThread;
        private static Task AcquisitionTask;
        /// <summary>
        /// The delegate function declares as field to avoid to be garbage collected
        /// </summary>
        public static Context.OnDevicesChangedDelegate handleDeconnection;
        #endregion

        #region Constructors
        static DepthCameraCluster()
        {
            depthCameras = new Dictionary<string, DepthCamera<T>>();
            stopThread = false;
            AcquisitionTask = null;
            UpdateCameraCluster();
        }
        [...]


        private static void UpdateCameraCluster()
        {
            Context = new Context();

            availableCameras = new Dictionary<string, ProductInfo>();

            using (var devices = Context.QueryDevices())
            {
                foreach (var device in devices)
                {
                    ProductInfo prodInfo = new ProductInfo(device.Info[CameraInfo.FirmwareVersion], device.Info[CameraInfo.Name], device.Info[CameraInfo.UsbTypeDescriptor]);
                    availableCameras.Add(device.Info[CameraInfo.SerialNumber], prodInfo);
                }

                foreach (var pair in depthCameras)
                {
                    if (!availableCameras.ContainsKey(pair.Key))
                    {
                        //Stop the processing thread of the camera
                        StopVideo(pair.Key);
                        Console.WriteLine("Depth Camera with Serial Number " + pair.Key + " lost connection.");
                    }
                    else 
                        StartCamera(pair.Key);
                }
            }
            handleDeconnection = new Context.OnDevicesChangedDelegate(HandlerOnDevicesChanged);
            if (handleDeconnection == null) Console.WriteLine("Handle deconnection null");
            Context.OnDevicesChanged += handleDeconnection;
            //handleDeconnection?.Invoke(null, null);
        }

        /// <summary>
        /// Function called when a new connection is found or delete
        /// </summary>
        /// <param name="removed_devices"></param>
        /// <param name="added_devices"></param>
        private static void HandlerOnDevicesChanged(DeviceList removed_devices, DeviceList added_devices)
        {
            string removed_devices_result = "Removed: " + removed_devices.Count.ToString() + Environment.NewLine;

            if (removed_devices.Count > 0)
            {
                for (int i = 0; i < removed_devices.Count; i++)
                {
                    string device_info;
                    try
                    {
                        device_info = removed_devices[i].Info.GetInfo(CameraInfo.Name) + " " + removed_devices[i].Info.GetInfo(CameraInfo.SerialNumber);
                    }
                    catch
                    {
                        device_info = "Cannot get info for device #" + (i + 1).ToString();
                    }
                    removed_devices_result = removed_devices_result + device_info + Environment.NewLine;
                }
            }

            string added_devices_result = "Added: ";
            added_devices_result = added_devices_result + added_devices.Count.ToString() + Environment.NewLine;
            if (added_devices.Count > 0)
            {
                for (int i = 0; i < added_devices.Count; i++)
                {
                    string device_info;
                    try
                    {
                        device_info = added_devices[i].Info.GetInfo(CameraInfo.Name) + " " + added_devices[i].Info.GetInfo(CameraInfo.SerialNumber);
                    }
                    catch
                    {
                        device_info = "Cannot get info for device #" + (i + 1).ToString();
                    }
                    added_devices_result = added_devices_result + device_info + Environment.NewLine;
                }
            }
            UpdateCameraCluster();
        }

The method where I register the delegate function is UpdateCameraCluster which is called during initialization of the class and normally each time a OnDeviceChanged event arise.

After some researches, I saw that to avoid this exception the delegate function should be declared as global. Unfortunately, this action didn't solve my problem any idea/suggestion to solve this problem.

Thank you for your help

Hugo