It's so weird. The competition companies don't have them (or very seldom and minor when they do), but CGC slabs are very often accompanied with NRs (even severe cases are so common these days that they no longer cause any double-takes). And yet CGC is like "Sorry, it's a natural occurrence. Nothing we can do about it."
Reminds me of a old job I had. There was a certain employee who arrived 10-15 minutes late just about every day. My boss was like "There's nothing we can do about it. He's got us over a barrel." because he was the only employee who knew how to run a particular machine. This is pretty much what CGC is doing. The vast majority of their submitters are CGC loyalists who refuse to either stop submitting or take their business elsewhere, so I'm certain CGC is like "What're they going to do about it. I'll tell you what they're going to do ... not a dang thing."