I can't get Animation Rigging to work correctly

Hello everyone. I have an animated character to which I apply Unity’s Animation Rigging so that at certain moments the character’s hand is at a certain point (Target). For this, I use the ChainIK Constraint component (I uploaded a video to Google Drive for better understanding). Everything works fine if the character is standing straight and looking at the horizon. But as soon as the character bends over or looks up, the hand goes out of the target zone. I don’t understand why this happens. I need the hand to always be rigidly tied to the target, regardless of the character’s position. How to do this correctly? Maybe there are other ways?