Sorry for the threadcromancy,
But I am also having this issue on LAN play, even when the LAN server is just me playing by myself (IE my gf who I play with hasn't connected yet) I get a crash to main menu and an Error Connection Lost (10).
Whats most frustrating is that this occurs randomly between 2-15 minutes gameplay so just when I think it's safe to play the game crashes/disconnects.