NullReferenceException thrown during touch interaction in WPF Pdfviewer Completed

HI,

Getting below error multiple times lately, but cause unknown, can you possibly diagnose from stack trace and error information provided below?

Many thanks

Stack Trace

NullReferenceException: Object reference not set to an instance of an object.
at Syncfusion.Windows.PdfViewer.DocumentView.UpdateOffset(System.Double offsetX, System.Double offsetY) at offset 0
at Syncfusion.Windows.PdfViewer.PdfDocumentView.PdfDocumentView_ManipulationDelta(System.Object sender, System.Windows.Input.ManipulationDeltaEventArgs e) at offset 760
at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate handler, System.Object target) at offset 7
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object target, System.Windows.RoutedEventArgs routedEventArgs) at offset 48
at System.Windows.EventRoute.InvokeHandlersImpl(System.Object source, System.Windows.RoutedEventArgs args, System.Boolean reRaised) at offset 230
at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args) at offset 87
at System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs args) at offset 20
at System.Windows.Input.InputManager.ProcessStagingArea() at offset 495
at System.Windows.Input.InputManager.ProcessInput(System.Windows.Input.InputEventArgs input) at offset 36
at System.Windows.Input.ManipulationLogic.ReportFrame(System.Collections.Generic.ICollection`1 manipulators) at offset 354
at System.Windows.Input.ManipulationDevice.ReportFrame() at offset 27
at System.Windows.Input.ManipulationDevice.OnRendering(System.Object sender, System.EventArgs e) at offset 0
at System.Windows.Media.MediaContext.RenderMessageHandlerCore(System.Object resizedCompositionTarget) at offset 138
at System.Windows.Media.MediaContext.AnimatedRenderMessageHandler(System.Object resizedCompositionTarget) at offset 46
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, System.Object args, System.Int32 numArgs) at offset 119
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object source, System.Delegate callback, System.Object args, System.Int32 numArgs, System.Delegate catchHandler) at offset 2
at System.Windows.Threading.DispatcherOperation.InvokeImpl() at offset 122
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(System.Object obj) at offset 27
at MS.Internal.CulturePreservingExecutionContext.Run(MS.Internal.CulturePreservingExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state) at offset 52
at System.Windows.Threading.DispatcherOperation.Invoke() at offset 15
at System.Windows.Threading.Dispatcher.ProcessQueue() at offset 229
at System.Windows.Threading.Dispatcher.WndProcHook(System.IntPtr hwnd, System.Int32 msg, System.IntPtr wParam, System.IntPtr lParam, System.Boolean& handled) at offset 63
at MS.Win32.HwndWrapper.WndProc(System.IntPtr hwnd, System.Int32 msg, System.IntPtr wParam, System.IntPtr lParam, System.Boolean& handled) at offset 48
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object o) at offset 54
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, System.Object args, System.Int32 numArgs) at offset 119
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object source, System.Delegate callback, System.Object args, System.Int32 numArgs, System.Delegate catchHandler) at offset 2
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, System.Object args, System.Int32 numArgs) at offset 187
at MS.Win32.HwndSubclass.SubclassWndProc(System.IntPtr hwnd, System.Int32 msg, System.IntPtr wParam, System.IntPtr lParam) at offset 285
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(System.Windows.Forms.MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(System.IntPtr dwComponentID, System.Int32 reason, System.Int32 pvLoopData) at offset 375
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(System.Int32 reason, System.Windows.Forms.ApplicationContext context) at offset 489
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(System.Int32 reason, System.Windows.Forms.ApplicationContext context) at offset 20
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun() at offset 52
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel() at offset 82
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(System.String[] commandLine) at offset 654
at PDF_Assist.My.MyApplication.Main(System.String[] Args) at offset 21