WA to remember last played map in an online/lan game.
When you join someone's game and the host selects the map, that map is temporarily 'saved'. That map is then automatically loaded when you start a "New Singleplayer-Multiplayer" game, however if instead you load a new LAN or Internet game, the map is lost and the default landscape is rendered instead.
I suggest WA should remember the last played map when starting both Online and Offline games, not just Offline.
This is done on purpose. Most of the time, you won’t want to replay on the same map as the last game, and sometimes the map is simply inappropriate (for the wrong scheme or audience). A map-maker could accidentally leak out an unfinished version of his map, which he’d rather leave under wraps until it was completed. Thus, I’d rather leave the current behavior as it is.