No doubt your dampeners are compressed judging by the cuts, to the point the dampener ends up consuming the shim, kinda like when you put your head on your pillow. I assume your running 716's on your machine? Watching your video it's clear in theory why it's doing what it's doing, the real issue is figuring out if it's a setup issue or not to bash by any means, a build issue. Like Rob is asking very valid questions. For me I feel as if the dampeners are being compressed to much and infact allowing the spindle to bend, I have never seen this happen with one of the synergy machines and frankly with any other vendor. Picture a (seesaw), with the dampeners installed in theory normal, you don't have the ability to rock that spindle back and forth per say . But if you compress the dampeners even more. You have swelled them to the point, they are tight as he'll, results being the blade grips have no relief when you introduce the loads you are introducing to them. With that being said, going back to the seesaw theory, like Rob asked where are the bends and where are the "marks in the head block" in relation to those bends, my guess is they are bent to the left and right of center "probably a few MM's from the threaded end. The shim has in fact become the Fulcrum (keeping the Seesaw image in your head). Again this is speculation only, weather it's plausible or not that's up for discussion pending more information, including the questions Rob has asked..
BR,
K