Same for me... Since the last update AI surface crashes the Editor.
The error.txt file in the Divinity Engine folder show this:
Size of AI grid and generated data doesnt match, please remove the generated.dat in your Editor\Levels\[LevelName]\AI\ folder
Size of AI grid and painted data doesnt match, please remove the painted.dat in your Editor\Levels\[LevelName]\AI\ folder
Size of AI grid and painted surface data doesnt match, please remove the surfaces.dat in your Editor\Levels\[LevelName]\AI\ folder
If I remove this 3 files, I could re-open my level. But when I re-generate AI grid it's impossible to reload the level... It crash again, even if I change the size or the paint of my terrain...
Thanks !