Rebuilt the diffs with the updated "black" shims today but none of the originals had any symptoms of deflection. All six looked just fine which makes me wonder what may have lead to the bent units posted earlier.

Edit: after further inspection, two of them have bent ever so slightly. Not to the extremes that others have posted but definitely something. Upper left and right in the image show it a bit but the other four are nice and flat. I dont know if both the bent shims came from one diff or not.