I run a production legal gen 4 G34. I've installed a Zev competition spring kit and trigger kit. I've also installed a tungsten guide rod with a 11lb recoil spring. On two random occasions in the past year, the gun has gun "full auto" or burst fire for 2 shots but only when engaging one target in entire match. See the vid below at minute 1:10. What's the problem? How do I correct this? Thanks