Pacifist bug/problem?

[Kaese]

No spoilers here.

So, I am playing completly nonlethal and stealth on Deus Ex difficulty on my first walkthrough.
Working my way to the Pacifist achievement while enjoying the awesome game. Sidequesting around and taking out some drugdealer people in a room only using the knockdown and taser.
When I walk out I double check for loot and suddenly see a skull icon instead of the "zZzZZ"-icon on one of them!
I am all like whaaaaaat and reload before I tased that first guy, doing it again. Everyone is ok, no alarm or anything. I pull out the taser and shock him like usual, silent nonlethal takedown... so I thought. Same skull again, which means he is dead? Reloaded and tried again, same result.

Screenshot, again nothing spoiling in there:
http://steamcommunity.com/id/Kaese666/screenshot/540651622657197768

Now I am kinda scared of this ruining the Pacifist achievement and even worse, what if this happend before without me noticing? People being dead for no reason only from tasing.

[Listen]

This is the Cloak and Dagger sidequest...This quest is documented to glitch sometimes, one of them being they seem to die if you drag them.

[Demon Wraith]

Some discussion here.
http://forums.steampowered.com/forums/forumdisplay.php?f=233&order=desc&page=2

Reports that it's a UI bug. But also that it causes failure on cloak and dagger because of killing.

[Kaese]

So that is the only place in the game with people randomly dying?
The quest isn't failing for me, but the achievement probably is.
I can just wait for a patch or try around till they all just go to sleep.

But I am worried this wasnt the first place with deaths.

[anticitizen101]

I've had people randomly dying in the Detroit sewers as well. Skullhead instead of ZZZ (and no they didn't fall in the water).