The pop-up "Host Connection Lost" - followed by a boot to the desktop, is a terrible implementation of a map change.
At bare minimum, the pop-up should say "The Bish/Rook/Nits have won the war! - But a new war has just begun..."
Then, clicking OK should take the player to the screen listing the arenas.
Making a player have to log back in is unnecessarily adding to the tedium. And with brand new players, the whole confusing event may turn them off completely.