Consider this scenario: An ArcGIS Server (10.3) hosted Map AND Feature Service, where the service is sourced from SDE. The Map Service is added to Portal (ANOTHER 10.3 server) using the "Add Web Service" tool in Portal. The ArcGIS Server is NOT federated to the Portal Server.
When adding the Map Service (item) to a Map in Portal, users can change the symbology of the features, in the Portal Web Map.
From a desktop 10.2 OR 10.3 client, when users are signed into Portal via the ArcGIS Administrator tool, and use the "Add Data From Portal" tool in ArcMap, when they add the Map Service via that Dialogue, they cannot change symbology. When they add the service directly from the stand-alone (not federated with Portal) server as an ArcGIS Server Service, they can modify the symbology in ArcMap.
The question is, is this the default behavior? If I hook a non-federated Map Service into Portal, ArcMap users of that service, using it through Portal, loose some functionality?
The whole point of Portal is to have a one-stop-and-shop place for data use and discovery for all of our data. Directing users to different service locations based on their intended end use defeats that purpose. Federating the stand-alone ArcGIS Server with Portal is not an option.
Interestingly enough, if I do all of the above, but with a Feature Service, users can change symbology in ArcMap, using the same workflow described above.