May just need to be broken in. Clean it good after each session. And keep shooting it.
It could otherwise be a number of things. Week spring, rough feedramp slowing down the bullets chambering, the slide catching too much of the magazine lips, etc.
If it doesn't stop after another 50 rounds, then I'd start looking at those other issues.
Most of the problems w/mine were fixed by polishing the feed ramp. But if you do just be very careful.