Issue with BetterNPC

I have BetterNPC which I use to add NPCs to monuments and a couple of random ones in biomes. 

I have just purchased this plugin and am testing and I would like to make them encounter and attack/kill NPCs on the server if I wish however there is an issue with BetterNPC. I have set them to not attack and at the moment they dont however sometimes one engages an idle NPC which it believes is a "heavy scientist" and the attacks seem to never kill the NPC so it gets stuck there forever just shooting. 

How can this be stopped?

you want to make them ignore BetterNPCs right? i'll look into that next week

Changed Status from Pending to Work in Progress

Yeah for the most part they do ignore them however when I have done a sweeping check I note one is showing up red with heading that is attacking a "Heavy NPC" and when I visually check I will see a BetterNPC standing idle while a RoamingNPC is attacking him. I am unsure what triggers this to occur as watching them for the most part they never attack or notice any BetterNPCs however maybe if a BetterNPC is triggered to attack an animal that may trigger the RoamingNPC to trigger an attack, not sure.

Ideally i'd like the option to have the BetterNPCs attack the RoamingNPCs since the aim of roaming NPC is to appear like a player but that kind of falls apart when they enter a NPC covered monument and attract no attacks. That is probably more a question for BetterNPC tho.