Control Rig IK Setup problem

I am not sure whether “Blueprint Scripting” is the correct section to put this in, but I hope so. So I tried to create a control rig for a synty skeleton, but when I got to the IK setup for the hand, the arm weirdly bends. Everything is explained in this video: UE4 Control Rig IK Pole Vector problem - YouTube

Hello! Have you found solution or workaround?