In Pro, I can add a group subtype layer. If I publish this to portal as a map image layer, it honors it and I have no issues. If i publish as a feature service however, it publishes successfully - but that group subtype layer simply doesn't exist. Layer id's will jump from 3 to 15 and skip over that group subtype layer. If I try to publish as a webmap instead, it says it doesn't support that data type, error 24078. Is publishing feature services with group subtype layers simply not allowed, or am I missing something?