It's already had a hot fix released which is working. Please update your game on steam.
Working? My game was just fine until I was forced to update. Now my character has animation glitches that make him hover as he's sneaking, and while I'm trying to aim in first person mode, it won't aim down the barrel on its own! I have to actually left click for it to allow me to aim properly again. That's a minor problem though, what the topic starter reported is a pretty serious bug. I've also seen those messages on screen and thought nothing of them, but a short while later I ran into a bunch of Deathclaws and Cazadors that were set to essential. When they're killed, they simply revive after a few seconds. I don't mean to be rude, but this kind of ruined the game for me tonight.