Any number of things can cause a handgun to be hitting away from point of aim. First, bench test it and/or have a shooter of known high skill try it. If it's shooting left in those circumstances too, it's probably the gun, and sight adjustment is in order.
Different shooter errors can cause a hit to the left. For the right handed shooter, it could be too little finger inside the trigger guard (and, for a southpaw shooter, too much finger). "Milking" the trigger will generally cause the shot to go to the non-dominant hand side, and down; it occurs because the other fingers are contracting in sympathy with the trigger finger, like milking a cow's udder. Quick fix: max force grasp with all fingers but the trigger finger.