At my range this weekend a gentleman with 400 rounds through his brand new GEN3 G19 had his first round hit him in the face. It got caught between his glasses and burned him just below the eye. Another with a brand new GEN4 G19's first round out of the gun hit him in the forehead. S no their are still problems.
Some run, some don't. Some are fixed with a little tweaking. Others won't run no matter what you do. like F106 said. You are taking a risk. Some run for awhile then have problems. But the newest ones are much better overall than a couple of years ago. Good luck.