I can't pull up your pics, but I am willing to bet the farm it's no (chipped) slide being the culprit. Being chipped from what? Whatever type of solid billit steel Beretta uses for their PX4 slide shouldn't chip in this century. I'd look to the slide release being re-assembled improperly, an issue with it's spring, the slide stop itself or something of that nature. Have you ever disassembled the slide release on your pistol? Do you primarily use the slide release to release the slide when firing the pistol? It is normal to see wear marks where the slide release and slide meet especially if you use the slide release to release the slide often when firing.