After patching up to 2.3, for some reason my neighborhood has separated into two layers. There's an upper layer that has nothing on it, and a lower layer where the sims, trees, water, roads, and lots are. Sims sometimes go to the upper layer when they're walking somewhere, but drop down to street level to go onto a lot. This occurs in multiple games, both on vacation and in the main towns, as well as on a new save in the custom town Zazazu made.
This is what the upper layer looks like:
And the lower layer:
Does anyone know what this is, or a way to fix it? Or is it the result of having a graphics card made of fail? Also, I don't know if this is relevant, but in the past my sims have appeared disjointed, but after patching the fat/muscle sliders don't separate their heads from their bodies.