csla: Azure Function App throws SerializationException: Unable to find assembly

Azure Function App throws SerializationException: Unable to find assembly at DataPortal.Execute. I’m using CSLA 4.7.100 but if seems to be a problem in previous versions too.

Stack Trace:

   at Csla.DataPortal`1.Update(T obj)
   at Csla.DataPortal.Update[T](T obj)
   at Csla.DataPortal.Execute[T](T obj)
   at ClassLibrary1.CommandObject1.Execute() in C:\Users\andre\source\repos\FunctionApp1\ClassLibrary1\CommandObject1.cs:line 23
   at FunctionApp1.Function1.Run(TimerInfo myTimer, TraceWriter log)
   at lambda_method(Closure , Function1 , Object[] )
   at Microsoft.Azure.WebJobs.Host.Executors.VoidMethodInvoker`2.InvokeAsync(TReflected instance, Object[] arguments)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker`2.<InvokeAsync>d__9.MoveNext()

This does NOT seem to occur when running a WebJobs project.

Any ideas?