I’ve been playing HL2 in Gmod with some mods, and after setting off the alarm in the capital building place thing I had to restart. And when I had to throw a grenade into a turret after restarting the level, it wouldn’t die any more. I tried killing other NPCs and they would die just fine, but the floor turrets just go “Fuck your grenades.”
EDIT: I am an idiot. All I had to do was reboot Garry’s Mod.
EDIT 2: Nope, it was Prop Protection.