OptiFine CEM models animations are broken

the vanilla animations work as intended, but if i want to re-do all of the animations from the ground up like this:

"left_leg.rx": "sin(limb_swing)*limb_speed"

the animation will work fine on regular mobs, but it won't work on the player that has turned into a mob, i was able to get around this by using the existing limb movement of the mob on the custom mob that i created, but it's really janky