Random ArgumentNullException when invoking operations

[Rans4ckeR]

As mentioned in my comment to the closed issue #119;
I now and then have an ArgumentNullException using net48 & 0.28.0-build06820 (net.tcp binding).
The stack trace is the same is in the beforementioned issue.

Type: System.ArgumentNullException
Message: Value cannot be null.
Parameter name: result
Source: System.ServiceModel.Internals
TargetSite: TAsyncResult EndTAsyncResult
StackTrace: at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.End(SendAsyncResult result)
at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
at System.ServiceModel.Channels.ServiceChannelProxy.TaskCreator.<>c__DisplayClass7_01.b__0(IAsyncResult asyncResult) at System.Threading.Tasks.TaskFactory1.FromAsyncCoreLogic(IAsyncResult iar, Func2 endFunction, Action1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---

application stack trace invoking the client here

--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.ServiceModel.Dispatcher.TaskMethodInvoker.d__16.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.ServiceModel.Dispatcher.TaskMethodInvoker.InvokeEnd(Object instance, Object[]& outputs, IAsyncResult result)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeEnd(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage7(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)