I don't have target analysis equipped, and regardless of damage type, a shock effect can be seen on the enemy when I shoot them. I reset my perk points to see if that was the problem, but to no effect.
You probably have the legendary quickhack. Short circuit or sth I believe. That makes the shock effect on crit hits.
After having 100% on the game: Most people dont die. Regardless of which weapon. Headshot kills, but only if the head explodes.
You can attack someone with Mantisblades and he/she is still alive. Very strange mechanic...
Legendary Short Circuit has a passive that triggers its damage on crit. This damage is electrical and non lethal. If you have Skippy and you are trying to get 50 kills to force it to switch modes, Legendary Short Circuit will prevent this from happening (because Short Circuit is dealing the incapacitating blow, not your bullets).
If you have quickhack perks, Short Circuit procs can do an astonishing amount of damage - in some cases, significantly more than the gun you are shooting or the melee weapon you are swinging. It adds roughly 40k non lethal damage to my katana strikes for example. It also applies to fists and this is how I was able to beat all the boxing missions with 3 Body and no stamina/melee damage perks in Street Brawling.
I been noticing this too and have been having to finish enemies off with a melee weapon or a headshot. The thing is, I don't have the target analysis nor the short circuit quickhack slotted and they're just the rare version. I wondered if it was one of my guns that has shock on it, but I think it's been doing this with non-electrical guns as well. I do notice some of the npcs hit often go down a few seconds later behind cover (not using tech weapons) like there is some type of damage over time (DOT) applied, but I haven't been able to figure it out as it seems to occur using basic guns that don't have any type of DOT. I'll have to test it more to double check. I wonder if using the short circuit hack or the target analysis in the past bugged and applied some type of no non-lethal effect is always on even though it is not slotted.