This seems to be a common problem in newer sizing dies, they just don't polish them like they used to! Last year I got a set of RCBS dies in 7.62x54 Russian, the sizing die leaves minor vertical scratches on the brass, a few months later I bought a Redding neck sizing die for 22-250, it does the same thing to the necks of my 22-250 cases! I've been reloading for around 40 years and had never seen that in any dies before, but both sizing dies from 2 different companies bought in 2006 are doing the same thing, and I've seen numerous posts from other people with the same complaint, it's strictly a cosmetic problem but it certainly doesn't look good! A few have reported sending the dies back to the manufacturer and getting a new die that does the same thing, and some people are resorting to polishing the dies themselves.
Previously the only time you heard about this kind of situation was when someone didn't think you needed to clean brass before reloading it, and had scratched their dies because of their carelessness.