IKFK match + scrub problem

When i switch from ik to fk and scrub the timeline, the animation gets messed up. As it is now, I believe its broken since i cant scrub backwards which i want to do. However, having read other scripts for ikfk match, they didnt go into solving this problem either.

Im using a blendcolor node to have the armCtrl.IKFK drive the bindjoints driving the IK or the FK arm. The armCtrl.ELBOWTWIST controls the armIkhandle.twist

//youtu.be/FHnXa_l5_uQ

any help? Is this how ikfk match is supposed to work?