Survivor starts autofiring?

My Zeta was firing single shots from his rifle but now hes firing 2 shots at a time after i levelled him up? Is there a way to turn this off? This wastes so much bullets and makes calculated headshots harder because of the increased chance of collateral damage......
Its just a skill when you lvl up and you cant turn of it, if you want to know more about the skill tap the skill right next to the survivor info !