I just registered to report the same problem.
While the issue does not happen to humanoid enemies, I am no longer able to kill Cazadors. Anything, including a headshot from a sniper rifle results in "Cazador is unconscious". Shortly they get back up, at full health, and resume the attack. There is no way to finish them off while they are unconscious because they are immune to damage and cannot be targeted via VATS.
I can't seem to kill anything wildlife. Dogs, Cazadors, Mantis about 50 percent of them just go unconscious, then get back up. didn't happen untill after the patch was installed. and it's effected the entire wasteland and any new characters i make.
THANK YOU BETHESDA was going on my 80th hour in NEW VEGAS and i totally needed a game breaking bug to move me onto something else!