1st shot in a volley immobilized the enemy, the 2nd shot then got increased accuracy. But all shots in a volley are supposedly shot at the same time, right? Is this desired behavior?
The accuracy of every shot, even
each projectile for a multi-projectile weapon, is calculated separately, and technically not until you see it fire, so yes this is normal. This keeps the situation (both this and other factors) more in line with what you see.
Edit: Also, if one of your weapons jams, the recoil penalty is applied to weapons before it but not in weapons after it.
True! This is because all weapons are fired in sequence but it's not until a given weapon is about to fire that it determines whether it fails or not due to system corruption. I could change it so that the chances are predetermined for consistency. (Corruption failure was a new mechanic tacked on to the process later...)