I'm playing with a couple mods, just weapon ones, bio Annihilation 2, and Gmod of The Dead Zombies. For some reason, when the zombies in Bio Annihilation 2 get up, they just... T pose. The T pose isn't what bugs me, its that they go invisible after, too. So the T-pose stays there, but the 'NPC' is still up, and still trying to attack you despite it not being visible. I dunno if this is a bug or not.