As mentioned we'll need a bit more information to be able to investigate and give you an answer.
Generally speaking the calls you are using to GeometryInfo and NormalGenerator are exactly the same in the 2 versions and are unlikely to be the cause of the issue. I'd say given the nice curved outer parts of the image that the geometry generated is about right.
Looking at the image my very first thought is that your z-buffer is not big enough and you are getting z-fighting. This would not be unexpected as the internal configuration of a Canvas3D and it's associated graphics context in back end is quite different between the 2 versions.
So to move forward we really need to see how you are setting up your Canvas3D in code and your hardware specs.
Then after that possibly a bit of debug output for the configurations supported by your driver and the defaults picked, which I can tell you how to get after you post the first 2 parts.