People who say this kind of thing never post example images. And I never believe anything anyone says without sample images. This kind of thing should be so easy to demonstrate I wouldn't trust anyone who could say something like that without posting relevant examples. The thing is, if he doesn't have relevant examples, how does he even know?
It goes to his credibility your honour.
There is way to much of this stuff posted on the internet. And honestly, unless someone posted relevant images on say an F*300 and a DA*300, I wouldn't believe he knew anything relevant to either of those lenses. It may be a problem some lenses have, I doubt all lenses have the problem, and with a general statement like that it's impsoible to know what lenses are affected and which aren't. OK, maybe the guy tested every old lens and every new lens and came to this conclusion, and has not one of his sample comparison pictures left to show us.
I don't believe that.
It's just some guy mouthing off.