This was also a problem in Fallout 3. Im surprised it isnt mentioned much. After I fire 3 or 4 shots in VATS the 4th, 5th, and 6th shot will be duds, meaning my character will rapidly fire 3 shots and do no damage. It also happens almost every time I target 2 or more foes in VATS. Furthermore, my ammo is wasted and of all my action points are depleted.
I currently have 2 characters.
My "energy weapons" character's primary weapon is the Tri-Beam Laser Rifle.
My "guns" character's primary weapon is the Brush Gun.
Will this bug be fixed with next update?