So, I recently started playing multiplayer with a friend, but we came to small issue. After some time (it usually is about two years, but we had one after only six months), he gets desynced. We play 1.3 and have no problems like that in normal game.
So, my question is: Do you know what causes it? I read that selling slaves may cause this problem and someone even mentioned dragon sieges. Can this be fixed somehow, for example if I manually change laws of all slavers to non-slavery or if I use Westeros-only submod (off topic question, in WO mod in ACoK and AFFC, is Daenerys there in form of some event, or do we just have to accept she will not come ever?).