Unfortunately, I'm out of simple ideas. Perhaps someone else can come up with something. At this point, I'd send it back to CZ.
Over the years I've learned a few things about sending guns in for repair. Write a letter and provide as much detail as possible. Some repair shops like to do pretty much anything they can to blame the shooter (I have not heard this about CZ), so you'll want to eliminate this possibility. I explain that the problem happens with both magazines, with different shooters (good idea to give someone else a chance just in case it's your hold), several different kinds of factory ammo (list the brands and type), and any other details that may be important. Since your problem happens pretty much every time, I would highly recommend that you shoot a video if possible. I've included a digital video on CD the last couple of times I sent a gun in for repair. If you can't do the video, it's OK. The other information should cover you. It's just a good addition if you can. Also, ask them for details of what was repaired. Some repair shops will tell you while others won't.
Definitely keep us posted. I'm very interested in finding out what the cause of this problem is.
The Lee Factory Crimp Die for straight walled pistol cartridges:
Your substitute for doing it right to begin with.