i had the focus point set to the center and aimed specifically at the eye for this...so it should have been focused there. but yea...now that you mention it i do see what you mean.
Well sometimes when the DoF is this shallow even the recomposing of the shot can change the actual focused area. One way to remedy this is to stop down until everything is sharp, or use a focus point that is closer to the eye.
You've already stopped down to f/8, any more and I think the lens would lose sharpness, so you kind of have to use another focus point to get it absolutely sharp. Not a big deal though, it's only soft when you look closely. If it was a print it would look just fine from normal viewing distance.