This. It's caused when the designers press "F" in the CS, which makes the objects fall to the next surface with collision. Which ends up in the colision meshes/boxes touching each other, which causes things to bounce around. Perhaps if ShadeMe added something into the CSE that altered this behavior it would help for future mods. But short of moving every single Havok'd object in the game slightly upwards you won't find a proper solution.
Actually, I am wondering now if my other problem is related to this. When I go outside, some crazy things happen like my horse falling from the sky into the middle of a lake, and animals being drowned in a cluster in water. Maybe creatures get dropped/bounced when the area's loaded? Although the range is much further in that case.
I might try the spell script thingy in any case to see if it makes any difference.