Creatures hover above ground
Not sure if it's issues with hitboxes or terrain, and haven't seen it on all creatures everywhere, but it's almost always on wildlife such as Mudcrabs, Rats, Guar, Kagouti and their corpses including Cliffracers.
It's really easy to see on slopes, here's a comparison MW (1) vs. OMW (2):
Interesting to note is, I've found that bodies of dead creatures (never been able to test it with live ones) initially spawn lower but hover upwards for a bit when you enter the cell.