I started a game as Magnar, named the world, and started the game.  While the world was being created, I alt-tabbed out, and that back in in.  My sovereign was there, but there were no icons, and no cloth map.  The sovereign could move around and build cities, and the cities could construct buildings and units, but there was no map.  I returned to the main menu and started another game, this time as Capitar, and the bug was reproduced, except this time the outlines and walls from the city I built in the previous game remained, although the city itself did not, and the sovereign began in the same position.

The text in bold is the only part of this which I haven't seen mentioned elsewhere in the forums.

The debug.err:

http://pastebin.com/m747f7bfd