In a handgun (in this case a CZ 75) when a malfunction occurs because instead of chambering the nose of the round is down below the feed ramp what is that a symptom of in most cases?
I’ve never had this happen in a Glock, just wondering what some potential causes are. The mag?
Thanks

most likely the magazine, but hollow,flat point or round nose bullets?....factory or hand load ammo, and if hand load do the cartridges freely pivot up and down if the top cartridges are depressed without striking the front of the magazine, and factory or aftermarket magazine?....sounds like the magazine is not allowing the cartridge to strip off cleanly, or slip under the extractor (how much extractor spring pressure?)...any dings or burrs in the magazine feed lip.... might try those first..

Nosedive malfunctions are magazine related.

Typically weak springs or feed lips.

If it’s a -75, I would guess weak springs. If a TS/TSO, I’d guess magazines which need to be tuned, particularly in 9mm.

Factory gold dot hp 124 grain + p. It’s fired them fine in the past.  
The mag is a CZ factory 19 round.
Good to hear it could be mag.

When I've had this happen, trashing the mag and getting a new one worked 100% of the time.

I've separated it from the rest.  Trashing it is a good suggestion.

If it's a gun you're going to shoot a lot, getting a supply of replacement mag springs from Wolff isn't a bad idea.

Or incorrect release from the magazine lips (to soon or late).

That’s still a mag issue, not the gun correct?

way back when, I had a TZ 75 (Italian clone), and had problems with cartridges slipping under the extractor claw

Usually.

Is this a new gun or old gun?  I wouldn't trash the mag.  You can always buy new springs from Brownells/Midwest gun works, etc.  Was the mag fully loaded and kept that way.  I had gen 1 Glock 19 rd mags that took a set and would not hold the slide release up.

Buy some Wolf +10% strength magazine springs.

If it's a 19 round magazine it's bot a +2 spacer/base on the bottom of a 17 round magazine.

I had issues with three of the extra capacity magazines (Mecgar) last year in .40 S&W.  Brand new.  They would barely raise the slide release up enough to catch the notch in the slide right on the corner.  Fearing damage at some point, due to the minimal contact surface patch I bought the Wolf +10% springs and they would snap that slide lock fully upwards into the slide notch.

Yeah, not a feed issue, but a weak magazine spring issue.  Those spring might be fine in a standard 12 round magazine, but the extended bases resulted in "weak" performance.

Had a similar issue with some M&P magazines last year with +2 bases on them.  Consistently failing to lock the slide back after the last round fired.  Wolf +10% springs fixes those, too.

One other thing.  Ever had the magazines apart to clean/lube the insides?  If so, did the spring get reinstalled correctly?  If the "front" of the spring isn't higher than the back it won't push up hard enough on the front of the follower.

I’ve never had the mags apart they’re only a few weeks old.
Shot 100 rounds yesterday using the 16 round mags, no issues at all.
I’m convinced it was the 19 round mag.
Thanks guys.

Try a new magazine spring first.

I would try a new spring and compare the mag to a known working mag.  I wouldn't just trash it out of hand.

Measure and compare to a good magazine.