The feet in game are twisting on the ground, while in animation preview (both from import, and from project window) they are planted. FootIK solver on or off does not matter. All bones match correctly in mecanim (hip is with hip, etc). And as shown in preview, the animation is solid. There is no reason for this counter-twisting. It makes NO SENSE. For future readers, (and myself). So when I made these animations, I left the hip bone alone. So I am guessing for some reason, when mecanim sees a hip bone with no keyframes, it rotates opposite of what the "spine" bone does. When I gave my hip bone a start and end keyframe (default rotation and location), the counter-twisting stopped. I still consider this a bug.