When AO is set to anything other than Very Low (basically off), it creates a weird striped shadowed effect at maybe the top 1 to 2 inches of the screen, specifically for areas of grass.
Not really as noticeable if you arent moving/panning the screen around, but as soon as you do, its pretty distracting and ugly. It doesnt seem to be rendering correctly at all.
You can clearly see it in the games 2nd zone, The Keepers Camp.