I starting sizing some 6.5 x 47 brass with my Redding Type S neck die, and it is scratching the hell out of the outside of the case necks. I took the die apart, cleaned everything, and it is still happening. WTH is going on?
I have the same thing with my 223 Type S with steel bushings. My 260 die with the TiN bushings is fine as is my 308 die with the RCBS WS2 bushings. Actually the RCBS bushings are giving me the best finish. The 223 with the lines on the necks shoots fine though.
I use the same die with 6.5x47 and 338LM. Both leave straight line marks on the outside of the necks with the TiN bushings but nothing major and they shoot just fine. No issues. Unless it's actually scoring the neck, I wouldn't worry. If you're very concerned, maybe take a bristle brush and run it through the bushing a couple times to clear it out just in case.
You may need something like a JB Borepaste to run through it. I've had the same thing happen (actually this morning recently) and ran a bronze brush with a patch smothered in it and it worked. Just don't go to town on it, just a few passes back and forth.