Skinned Meshes Deform Incorrectly on iOS Device

Not getting anything useful in the user forums so posting this here, hope somebody has seen something like this before.

I've got a bunch of characters doing all kinds of stuff on an island. They look great in the Editor, but as soon as I output for device, meshes start deforming incorrectly. See attached image. Anybody know what's going on here? My quality settings have blend weights set to 4 bones. Is there some iOS setting I'm unaware of? Thanks in advance!