While fighting at the crown i fell threw the map, decided to run back and record a video of exactly where i fell threw to help with removing this bug.
And this and this http://forums.station.sony.com/ps2/index.php?threads/found-a-new-fall-through-the-world-bug.80702/ http://forums.station.sony.com/ps2/index.php?threads/terrain-placement-bug.80728/ So it means there has a wrong point, it feel like the rock should be on the top of your head and you should stand under the ground...