Why does't it get the roomlist when a new client join a lobby?

My code is follow:

public override void OnConnectedToMaster()
    {
        base.OnConnectedToMaster();
        Debug.Log("LaunchNetMgr OnConnectedToMaster");
        if(ConnectedToMasterEvent != null)
        {
            ConnectedToMasterEvent();
        }
        
        //加入Mar大厅
        TypedLobby typedLobby = new TypedLobby();
        typedLobby.Name = GlobalParam.Ins.lobbyName; //lobbyName is MarLobby
        typedLobby.Type = LobbyType.SqlLobby;
        PhotonNetwork.JoinLobby(typedLobby);
    }

when OnConnectedToMaster is called,join a custom lobby called MarLobby

after joined the lobby,the client will create a room to wait other player join autolly


in normally, when another player join the same lobby called MarLobby,
OnRoomListUpdate will be called and get the exist rooms

now, the problem is that "when another player join the same lobby called MarLobby, but OnRoomListUpdate can't get the first player craeted rooms, the room count is 0"

why? and how to fix the problem? thank u for any reply