Okay, now for the explaination of the bugs. In the first screenshot, there are 2 bugs. The first is the more obvious terrain issue. Before this happened, I minimized the game and brought it back up, followed by using a terraforming spell (raise land). The change seemed to be temporary and/or only graphical, as it reverted to normal when I built a city within the region.

The second bug is the smaller terrain display issue (second circle) involving those line going through the map. I would assume those divide the map into sections, and when minimizing and un-minimizing the game regularly creates those sort of bug. I have seen it displayed as terrain, displayed as un-explored area, and returned to normal via minimizing and unminimizing.

The third bug involves a vanishing city. I attacked the enemy soveriegn in between turns, and as the game likes to keep targeting the enemy sovereign even after they are defeated and teleport back into their cities, my sovereign them attacked the city (about 1 or 2 squares away at the time). Since it was well defended, I retreated. I was then attacked by the lone sovereign, defeated her, and then the turn finished. The city had then vanished entirely, along with the enemy sovereign (to my knowledge).

Edit: It seems I won the game, causing the third bug... Dunno why defeating a faction would make the cities vaporize rather than making them neutral capturables though. On another note, yay! A full game with only 1 CTD!