hi, I checked for you using the car turrets plugin and the turrets from that are killing the npcs when Player Traps And Turrets Ignore Npcs is set to false
Block Damage Outside Of The Dome To Npcs Inside can block this damage if you are not inside of the event. it does not matter if the npc is outside of the event, it will still be blocked (until next update because that's weird)
otherwise there are no settings that would block it, so it would have to be some other plugin breaking the functionality somehow