UWP System.Runtime.InteropServices.COMException in async method

I tried to modify the code from Windows universal samples for BLE Advertisement and got the System.Runtime.InteropServices.COMException:

private async void OnAdvertisementReceived(BluetoothLEAdvertisementWatcher watcher, BluetoothLEAdvertisementReceivedEventArgs eventArgs)
        {
            if (!connected)
            {

                StorageFolder storageFolder = KnownFolders.DocumentsLibrary;
                commandFile = await storageFolder.CreateFileAsync("command_to.txt", CreationCollisionOption.OpenIfExists);
                resultFile = await storageFolder.CreateFileAsync("result_from.txt", CreationCollisionOption.OpenIfExists);

                BasicProperties fileProperties = await commandFile.GetBasicPropertiesAsync(); //Here I get the COMException
                commandFileVersion = fileProperties.DateModified;

            }
        }

This method fires every time I get BLE Advertisement. And almost every time it works fine, but sometimes I get COMException on GetBasicPropertiesAsync().

The whole Exception message:

-       $exception  {System.Runtime.InteropServices.COMException (0x8000000E): A method was called at an unexpected time.

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at g831ble.MainPage.<OnAdvertisementReceived>d__10.MoveNext()}   System.Runtime.InteropServices.COMException