Question Mecanim humanoid animator transitions have gimbal lock.

So I'm about at the end of my rope here. I'm not sure why, but several of the animations I've made are having this terrible issue with gimbal lock/gimbal flipping during transitions. Where the arms and hands most of the time want to do a 360 degree spin just to end up in near the same position they were supposed to be. This is only during the transition.

In this animation, both arms and both hands are doing it.

The animations are humanoid and all share the same avatar.

I'm aware that humanoid animations all interpolate via quaternion, but apparently transitions between animations are interpolating with eulers??

Has anyone else had this issue? Is there any way to change the way transitions are interpolated? Or I am I forced to modify the animations blindly until this issue is gone?