Age of Ice bug: Upgrading heroes causes interface weirdness

[Neonanocyborgasm]

While playing Age of Ice (BTS 3.03), after I had seized the hilt of the Godslayer and brought it back to the capitol, I also upgraded Caerbulin to an assasin. After that, the interface started getting screwy. It would display the city screen and the regular map screen at the same time, and I could even move some units around through that screen. When I saved the game, then reloaded it, this weirdness went away, but there were others. For example, no matter what stack of units I selected, it would always display the same set in the lower part of the screen. Sometimes I couldn't select the unit I wanted at all. I also couldn't upgrade any more of my hunters to assassins, even though I had hunting lodge in that city. (I know because I was able to build assassins in that city, but not upgrade hunters to them. It didn't even give me the option, so it's not as if I lacked the gold.)

Save game attached.

I think I had this problem before in a previous game. I believe what happens is that when you upgrade a hero, this bug appears.