I have not had a single issue with either of my Gen 4 models. I have the 17 with over 5,000 rounds through it and just bought my 19 Tuesday morning so it only has a couple hundred so far. If your gun is working then don't worry about it. Just get out and shoot it enough so that you feel confident in it.
"They're on our right, they're on our left, they're in front of us, they're behind us; they can't get away from us this time."
Chesty Puller, USMC, Chosin Reservoir, Korean War
"You cannot exaggerate about the Marines. They are convinced to the point of arrogance, that they are the most ferocious fighters on earth - and the amusing thing about it is that they are."
- Father Kevin Keaney, 1st MarDiv Chaplain, Korean War