So I had a game reach just over 300 turns, and I had a very strange bug occur.

When my cities leveled up from lvl 3 to 4, all the housing in them disappeared.  The tiles they occupied became unavailable, but I did get the building slots back, which I could use for other buildings.  At the time, when I brought up the building options, Villa's (the housing tech available) were nowhere to be found.  Upon a reload of the game, as it crashed shortly there after, the Villa's were once again available to be built.

I didn't notice it at first, and actually started building some big buildings in my 22 pop level 4 city, thinking, wow how did so many slots become open here?! hehe

The debug should be before the reload.

Debug

Dxdiag

Screenshot

Autosave

If need be, I can try and recreate the bug for you guys.