I think I see what is happening., for starters you have this set to false
"Only Allow Event Owner/Team to Attack Deployed NPCs": false,
So this should mean anyone can hurt/kill the NPC. But because my plugin assigned them an OwnerID, I assume one of your other plugins, such as LootDefender maybe, or another similar PvE plugin that prevents other players interacting/damaging owned entities, in this case the NPCs. I will release a fix to address this shortly.
As an FYI, if you only want the owner and team to kill the NPC, you should change this to true, after the fix:
"Only Allow Event Owner/Team to Attack Deployed NPCs": true,