When you're nesting anchors, each anchor won't know who goes first, so you will get potentially weird movements if you let them turn off after only one frame.
Optimally, you'd run them downwards in the hierarchy once and then turn them off.
You can make your own script that runs each anchor's update() and sees if the position changed because of it, if it hasn't then destroy the anchor. Make sure you run this in the right order though.