At this point in time, ESRI Portal for ArcGIS does not support subtype layers, so we are using query layer to publish our Gas Utility Network to Portal 10.6.1. The problem is that if we have all of the query layers (Device, Assembly, Line, Junction) in one map, all domain code descriptions do not show up, only the code values show up on the popups and attribute tables. However, if we separate those feature classes into different maps, e.g. Device in one map, Assembly in one map, and so on, and publish them, the domain code descriptions show up as expected, see attached.
Is this a Portal bug? or am I missing something?