Okay, some questions.
one - do you run the magazine empty, leave the slide locked to the rear, remove the empty magazine, insert the new magazine and then use the slide release to let the slide go forward and chamber the first round in the magazine?
Done this way, the slide uses the full force of the recoil spring to strip the top round from the magazine and chamber it.
two - do you run the magazine empty, leave the slide locked to the rear, remove the empty magazine, insert the new magazine and then grab the rear of the slide and pull it to the rear (to unlock it from the slide release) and then let it go so the new round can be stripped from the magazine and chambered? If you do it this way, do you totally let go of the slide when it reaches full movement to the rear? Or do you try to keep it from slamming forward so hard by "riding" it forward a certain distance?
If you "ride" the slide it can cause feeding/chambering issues.
Either use the slide release or pull it to the rear and just let it go.
If it still fails to feed/chamber that top round when you release the slide correctly then you've got other issues that need to be addressed - possibly by CZ. If the pistol has issues CZ USA can take care of it pretty quickly.