Built a cutter for pve bounty hunting/assasination, one fixed class 4 auto cannon long range/corrosive shell, rest beam turrets. A 7A G5 weapons focused/super capacitor with 3 pips can pretty much perma fire a mix of 2 class 3 long range and 4 class 2 efficient beam turrets and leave enough left over for the class 4 auto cannon to finish up.I've never encountered this issue...nearly all of my turret equipped ships have only fixed weapons and turrets.
Idea was to strip shields with the beams, and when they ran, and npcs quite often do once you get them down to 20-40% hull, give them the fixed auto cannon in the backside. Usually took out their engines in seconds.
Only problem is that the turrets would not fire. assigned them a fire button, set them to fire at will or forward, and nothing. They would not shoot. Replaced fixed with gimballed auto cannon and it works, switch back and no worky. Perhaps it is something they fixed, or it is a glitch that only affects some installs. I did submit a ticket back when it happened.