Chances are the spring tension in your magazine is causing that round to push hard againt the bolt. Then when the 1st empty casing is cycled out the bolt is hooking on the round below and causing the front of the cartridge to misalign. Your next round would cycle fine because the spring tension is less and less as you empty the mag.

Generally this is fixed by squeezing the lips on the top of your magazing together slightly. Or you can try a new magazine.