I noticed that on the latest release shadows drawn by shaders are also getting moved when the player moved the camera.
I guess this is due to the nature of the shaders but could there be a fix for that?
I am thinking of a solution to tell Minecraft that the anchor point aka original camera is still in the players head but you use the third person cam instead.

Keep up the work.

Here is a gif to showcase this: Click

Switching to the dynamic crosshair might help but this is really an issue of optifine. The is not much i can do on my side atm because of #21

If you want this fixed you should submit an issue at the optifine repo