It's looking more and more like I was right on the money regarding the design change with every bit of new info. As I've mentioned elsewhere, CZ is already having a hard time keeping up with demand for new mags, especially 30 rounders. I think their reluctance to issue a recall over the older mags in favor of simply replacing them as they fail is just a way for them to avoid getting their inventory zeroed out for new mag bodies for the next few months or longer as every distributor, retailer, and end-user floods them with mags that technically still work but have a more failure-prone design.
I agree that the mags should have been good to go from day 1, but at the same time, things like this do happen in the gun world, especially with newer designs. Even Glock has fallen on their face once or twice. At least in our case, we'll only need to replace a $20 magazine instead of getting taken for a ride like Sig MPX Gen 1 owners did, for example. I'm just glad Hillary didn't win or this would be a far more urgent and potentially unsolvable problem. CZ really lucked out in that respect.
As for 2016 Type B magazines cracking, the only examples I can think of were part of copenhagen's testing, where the degradation of the polymer was caused by a chemical reaction to Militec-1. The "control" mags and those sprayed with Ballistol held up just fine staying loaded over the course of a month. I've also got a loaded Type B in my nightstand that's been there for about a month and a half and doesn't appear to be failing either.
