Yes, I was extra careful too. CZ sent me the return label to ship via Fedex. I placed rifle in a hard plastic case, put the mags in ziplock bags and sharpied on to them what the issue was, placed them inside the case too, locked the hard case with zip ties, and then placed the case in a large cardboard box filled with newspaper for packing materials. I even sharpied my name on the hard plastic case. I took every precaution I could think of at the time.
CZ did tell me the box arrived from Fedex in good condition, so it wasn't that something "dropped" out. It certainly wasn't that someone along the way opened the box, took the mags, but left the rifle. It was (at least in my mind) a case of the first person to unpack the box being "busy" when it arrived, and they just didn't inventory it correctly. The manager admitted that there are "punishments in place if information is inputted incorrectly" on arrival. And how do you ever know if the employee messed up, if you ALWAYS trust the word of the employee over the customer? The manager was careful not to call me a liar explicitly, but it was implied that I was either being dishonest or incompetent. Of course, "punishments" can be a double-edged sword, because it means if the employee makes a mistake they are unlikely to admit it and face a penalty of some kind. Honestly, the attitude of CZ is basically that you just have to trust that we would never inventory a shipment incorrectly.
I believe one day, while someone at CZ is digging around in the stuff that is undoubtedly just lying around in their receiving area, they will find a nice big ziploc bag with two 527 mags inside labeled that there is an issue with them, will wonder where they came from and who's they were, and then will just toss them into another drawer.
At any rate, I'll get the rifle back in tip-top shape, with a brand new mag. Someone will snag a pretty good deal once I put it up for sale.