Adding a feature layer to a map by consuming a map service having a label expression consisting of concatenated fields as opposed to a single field fails to draw labels along with the feature layer.
Bug ID Number
March 19, 2015
December 1, 2020
After review by the development team, it has been determined that this issue is related to a known limitation with the software that lies outside of Esri's control. The issue's Additional Information section may contain further explanation.