I was able to fix the replication of player and lobby state in my project by reordering some of the setup functions on the host.
Make sure you are calling them in the following order:
AOnlineBeaconHost::InitHost()
ALobbyBeaconHost::Init(SessionName)
AOnlineBeaconHost::RegisterHost(LobbyBeaconHost)
ALobbyBeaconHost::SetupLobbyState(MaxPlayers)
If you are calling SetupLobbyState prior to RegisterHost, the lobby state will be unable to set up replication because it can’t find the net driver name. This then chains every time a playerstate is created, grabbing the same empty net driver name.