[Will Campbell]

It could be just a defective piston, but it is much more likely to be from unexpected operating conditions.

Broken at the land- looks like detonation damage.

Assuming natural aspiration, it is probably a result of too much timing, or too lean a mixture under load. If forced induction, well, that should be obvious.

Is it a stock tune? If so, perhaps there is an air leak after the sensor, perhaps at the manifold.

New LS7s come with a 2 year 50,000 mile warranty.