Ok then now we are on to something. I tried everything, ammo, recoil springs, connectors, grip and nothing worked. Sometimes 2-3 time a mag and other times 3-4 mags with no issue.
You might be quick to nay say this and it made no sence to me with my G34. Take the slide completely apart and clean the crap out of it. Clean through the striker channel and the extractor spring channel, clean the extractor and channel out real good too. Of course inspect everything real close for burrs and what ever. When you put it back together use more oil, put a little oil on your fingers and wipe the strike spring, extractor spring and extractor. Oil the groves in the slide like you would on a 1911.
I know this sounds crazy.... But when I did it my problems went away and did not return. Maybe a piece of junk it just the wrong place of or friction somewhere. In my gut I think it was a lube issue, but not sure. Now I wipe it down every 400-500 rounds and re-oil and no more issues.
Its actually funny you say that, because that was my first thought, take apart and hella clean the gun, but I passed it off as no it has to be something I've added on.
I will give this a try hopefully this week and follow up