Cannot host a world if the world is opened under cellular network

When I open a world under cellular network (4G LTE), it is in single player mode. I cannot host the world and let my friends to join. It seems multi-player mode is only supported if the world is opened under WiFi network.

I am not sure if this is a design that multiplayer mode is only available under WiFi network. But after I open a world under WiFi network, then switch to cellular network, I can still invite my friends to join.

Besides, if I open a world in cellular network, trying to use PING API to query information of the current world, the data field of ID_UNCONNECTED_PING_OPEN_CONNECTIONS is empty. And as single/multi-player mode, if I open the world under WiFi network then switch to cellular network, the PING just works fine.