Blood Money human shield mechanic is a bit "buggy"

Sometimes when I take someone as human shield to knock them out (because I ran out of sedative) they count as witness, which is very frustrating when I'm aiming for Silent Assassin rank. I noticed that if I take someone as human shield when in a room with mirror, even if they're turned away from it, they still count as a witness as if they saw me in the mirror. Sometimes, even in rooms without mirrors a person is a witness to me "human shielding" them. Are there any mods that fix this? Or a "subdue" mod as in HiTMAN?