Using ArcGIS Pro 2.2.3, I added some layers to the map from Enterprise (the product formerly known as ArcSDE)
I then ran the Package tool with the Reference all data for Runtime checked, and Support for Runtime checked.

I then create a new LocalMapServiceLayer, passing the path to the mpkx file, and StartAsync() on it.
I then get an error saying:
Failed to create service avecc_elec_components2 MapServer. Service failed to initialize: The map package is not supported by the ArcGIS Runtime. There is no .msd file available inside the package. Check that it was authored with ArcGIS Runtime support enabled.
I unzip with 7zip and confirm that there is no .msd file present.
Does anyone know of a way to load a package into Local Server that just references the ArcSDE featureclasses?
Thanks, Kirk