Updating Moho Object reference messes up feet angles

[kakubei]

Hello friends, me again...

I've got a situation where I have a Moho character with IK and IK/FK switches.
The feet bones I've set to Independent angle.

I use this character a lot in different scenes and import it by reference.

Yet, whenever I update the reference, the feet angle get invariably messed up. I can't figure it out. They've got keyframes and I haven't changed the animation.
Plus, the foot bones are not part of any existing Actions.

Anyone have any ideas?

Thanks.