There have been discussions on DPR and FM. And as Ian said, you can also try it yourself. If I remember, the bokeh issue was illustrated nicely by Fred Miranda himself, but can't remember if it was with a 50/1.4ZA or the 35/1.4 lens. It was back yard pics with foliage in the background. I'm going to guess that Nikon tried to optimize for the Z-mount primes to maintain their out of focus rendering without this EFCS artifact. But it's all about trade-offs.Source?