HL2 in Gmod: God floor turret

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.

I thought the HL2 campaign was broken in GMod; surprised you got that far.

So far, it seems to have been working very well, except for the floor turrets which were working at first and then decided not to work anymore.