It's only an issue with the Borealis. If you haven't bought them, you wouldn't have experienced it. Chessex or not, this is a problem with this specific line. And doing some research, this is a known issue that's been brought up on this sub before and can be found in the reviews for these type of dice.

One of the reviewers even mentions contacting Chessex:

EDIT: I contacted Chessex and they responded quickly; apparently the scuffs are mold marks (they provided pictures to show that all of the borealis and translucent dice have them). Oh well. Added two stars because of good customer service, not full because of the marks though.

Yes they came in the usual packaging. Yes, they're Chessex dice. Sparkly dice have enough draw that anybody making "counterfeit" could probably just brand their own and sell them without the need to fake the Chessex label. I suspect that places like Amazon (or its sellers) are just buying off the B Grade dice for cheap to sell. And yes, Chessex has B grade dice, every manufacturer does. Where do you think their Pound of Dice comes from?