I can answer this one. The boxes (cardboard in general) contain a lot of impurities, it's not just thick paper. These impurities act like metal filings or sand, and will scratch blades. And that's any blades, I had scratches on anything from Gin-1 to BG-42 to VG-10 to CPM30V.
The cutting of boxes is actually something I warn anyone considering purchasing a sword about. Because nothing is worse than waiting weeks to get a $500 cutting sword, looking all over how pretty and even it is, and not resisting the sudden urge to cut its shipping box in half. I mean, it's always a nice rectangular box, a perfect cutting target unless you went ahead and got tatami mats soaked or bought pool noodles to cut. So almost everyone, with their first sword, goes after the box. And depending on the quality of the box (some cardboard is more abrasive and some not so much) the blade can be badly, badly scratched up.
So yeah, boxes will take a beating on the knive, at least in my experience. Harder steels will last longer, but even they will scratch up eventually. You can try to polish it off, but if it's a user knife, might as well accept it. My serrated Spyderco Military and plain edge Delica look like hell, but they are also my favourites because those same scratches give the knives a lot of character.