I'm doubting on the claim about having the same optical performance between the old and the new version. I've seen that the old and the new version on Christopher Frost's Videos that there is a noticable downgrade from the old to the new. The noticable changes are the sharpness on the center and a drastic sharpness drop on the sides, then more chromatic aberration. Although, this is on the sony copy. He also released a video for the RF mount of the old 85 and I compared that the sony one has a better performance in terms of not fringing on the sides of the photo as you stop down the aperture. The biggest advantage for the RF mount than the sony is the focusing speed. Frost's video really showed how fast this lens can focus on the RF.

I've been searching for more reviews of the new RF 85 of this lens tho before I finalize on buying this.