I've come across a fascinating and baffling bug. The game will be fine until late era, like when I'm researching plastics and that stuff, and one of my units will suddenly no longer have command buttons when selected (fortify, sentry, etc etc). It'll be selected, and I can right-click-move it around, but I can't tell it to DO anything unless I use hotkeys.
At first only one or two units will be like this, then more and more of them over the next few turns.
Then the bug attacks cities. selecting a city's production by clicking on the city's info bar will not have buttons for different productions. Nor am I able to set production by going to city info screen.
Then it gets weirder. Once I've entered a city info screen, when I hit escape, the map zooms back out, but the whole city info border is still there. Won't go away. And there are now fewer things on the map I can click on.
The persistent city border can be cleared by changing the video resolution, but when I do that, the ENTIRE UI disappears all save the little red 'next turn' circle, and the flag below it. Everything else is gone, no UI at all. I can still hit ESC to access the menu though.
Okay, now here's the REALLY weird part.
When I go back to a savegame before the bug hits, and play again, the bug will happen again, over the same number of turns, in exactly the same progression, exactly the same way, down to each individual unit that starts bugging first.
So far this whole rigamarole has happened in 3 games, but at different (but all late game) points. Also, playing vanilla civ4 without the mod exhibits none of this odd behavior. As an additional note, I'm playing on lowest graphic detail settings and no AA, to (partially) avoid the dreaded memory-leak-crash (it seems to help a little).
Sooo.... any ideas here?
edit: btw, I always play with 'new random seed on reload'.
That's the problem. 
