So I was doing some pistol/carbine training yesterday and my instructor was having me do speed reload drills. Before the drill, I locked back the slide and loaded one cartridge into the chamber by hand and released the slide. I then fired the handgun without a magazine inside and then reloaded a full magazine into the handgun. When I tried to power stroke the weapon, I looked down and saw the first shell failed to extract. (see picture below) Anyone know what could of caused this? I've ran about 500 rounds through this weapon so far with no problems. I have fired it before without a magazine inside too. My instructor was confused as well, he said he had never seen a Glock do this before in his lifetime. He suggested limp wristing or a bad extractor. I did fire it the rest of the day without any problems, so I'm hoping it's a one time deal.