EOnlineDataAdvertisementType doesn't work

I’m having problems retrieving the session settings correctly on the client. Every extra setting is set to EOnlineDataAdvertisementType::ViaOnlineService, when using the OnlineSubsystemNull every key exists in the settings map, but the data is always empty. With OnlineSubsystemSteam the whole map is empty. Every other setting is correctly available on the client. What do I have to do get the custom session settings on the client?

It seems like uint32 and JsonObject are not properly send to the clients.