Weird, my overture with "only" a Pax on it, never kill any enemies
Not tried Cyberpsychos in 1.52 yet, but I had no problem with them during 2 playthroughs in 1.5 (Always use Overture & Quazar with only Pax). I imagine that it could be "easy" to kill them by hiting them once they are down with a high firerate weapon (non-lethal weapons kill enemies when they are knockout, even if non-lethal mods are installed).
Anyway, you can report it to the support, if you want, if it's not already done and if you don't use mods (with save)
It seems like non-lethal blunt weapons have never been non-lethal when it comes to cyberpsychos. A regular old baseball bat hits twice when using it to hit once; when the psycho's health is down really low, I find that I have to hop back with my character before that second swing hits or risk killing the psycho. I'd like it better if they non-lethal was always non-lethal.
Once "knocked out" if you hit enemies again with blunt or non-lethal weapons they usually kill. This means that if an enemy is down, you can go back and kill them, or by accident kill them on a double swing or shot. Makes it hard to NOT kill if that is your desire.
IT does allow you to get extra XP by knocking them out, then going back and shooting them, as example use the cyber hack poison to knock most enemies down, then use a pistol to get more XP by executing those knocked out. IT also allows you to easily get the achievement on the skill to jump down on 3 enemies and kill them with the cyberware...knock 3 enemies out, pile the bodies up and then jump down and activate the power landing and poof 3 dead and achievement.
The enemy cannot believe that you defeated them and they die of embarrassment
You are suffering from an ancient curse IRL
The computer hates you
There is no way that I have seen to prevent it from happening. If it is important to a mission, saving before the fight is the way to go. If the enemy dies, re-load the save and keep trying until they don't die. I had to do most Cyberpsycho missions two or three times, before my non-lethal weapons successfully kept the psycho alive.
If I notice that I've killed the cyberpsycho while reading at the message for Regina with my non-lethal weapons, I simply reload the last save game. This always brings my back to the moment i've defeated the cyberpsycho who now is just unconcious.
I just finished all the Cyberpsychos in a row and I killed two due to the legendary Short Circuit passive effect (I simply reload, so it wasn't a problem).
In short, if you use a high firerate weapon (in my case Psalm 11:6), if the psycho have a "low life" and you deal a crit damage in a middle of a "burst", there are great chances that the passive Short Circuit effect will knockout the dude immediatly and the "remaining" bullets will kill him just after