Even when set to false in the config, NPCKills still shows in the leaderboard and the BotHunter Tag is still being assigned to the leader. Config pasted below 

{
  "Challenge Settings": {
    "AnimalKills": {
      "Title for name tag": "Butcher",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 0,
      "Title priority": 19
    },
    "ArrowKills": {
      "Title for name tag": "Archer",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 1,
      "Title priority": 20
    },
    "StructuresBuilt": {
      "Title for name tag": "Architect",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 2,
      "Title priority": 23
    },
    "ClothesCrafted": {
      "Title for name tag": "Tailor",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 3,
      "Title priority": 25
    },
    "ExplosivesThrown": {
      "Title for name tag": "Bomb-tech",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 4,
      "Title priority": 28
    },
    "Headshots": {
      "Title for name tag": "Assassin",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 5,
      "Title priority": 14
    },
    "PlayersHealed": {
      "Title for name tag": "Medic",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 6,
      "Title priority": 31
    },
    "PlayersKilled": {
      "Title for name tag": "Murderer",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 7,
      "Title priority": 13
    },
    "MeleeKills": {
      "Title for name tag": "Fighter",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 8,
      "Title priority": 21
    },
    "PlantsGathered": {
      "Title for name tag": "Harvester",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 9,
      "Title priority": 32
    },
    "PVEKillDistance": {
      "Title for name tag": "Deadshot",
      "Enable this challenge": false,
      "Position in the UI leaderboard": 10,
      "Title priority": 22
    },
    "PVPKillDistance": {
      "Title for name tag": "Sniper",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 11,
      "Title priority": 17
    },
    "StructuresRepaired": {
      "Title for name tag": "Handyman",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 12,
      "Title priority": 24
    },
    "RevolverKills": {
      "Title for name tag": "Gunslinger",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 13,
      "Title priority": 18
    },
    "RocketsFired": {
      "Title for name tag": "Rocketeer",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 14,
      "Title priority": 26
    },
    "RocksGathered": {
      "Title for name tag": "Miner",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 15,
      "Title priority": 27
    },
    "BladeKills": {
      "Title for name tag": "BladeKillsman",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 16,
      "Title priority": 16
    },
    "WeaponsCrafted": {
      "Title for name tag": "Gunsmith",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 17,
      "Title priority": 29
    },
    "WoodGathered": {
      "Title for name tag": "Lumberjack",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 18,
      "Title priority": 30
    },
    "HelicopterKills": {
      "Title for name tag": "HeliHunter",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 19,
      "Title priority": 12
    },
    "APCKills": {
      "Title for name tag": "TankHunter",
      "Enable this challenge": true,
      "Position in the UI leaderboard": 20,
      "Title priority": 15
    },
    "NPCKills": {
      "Title for name tag": "BotHunter",
      "Enable this challenge": false,
      "Position in the UI leaderboard": 21,
      "Title priority": 33
    },
    "QuestsCompleted": {
      "Title for name tag": "Adventurer",
      "Enable this challenge": false,
      "Position in the UI leaderboard": 22,
      "Title priority": 34
    }
  },
  "Options": {
    "Ignore kills against sleeping players (Players killed)": true,
    "Ignore explosive kill distance": false,
    "Kills against NPC players are counted seperate to player kills": true,
    "NPC kill distance counts as PVE distance": true,
    "Show challenge leader title tags (Requires BetterChat)": true,
    "Ignore all statistics recorded by admins": true,
    "Ignore kills for event players (Players killed)": true,
    "Ignore supply signals thrown (Explosives thrown)": true,
    "Ignore survey charges thrown (Explosives thrown)": true,
    "Ignore flares thrown (Explosives thrown)": true,
    "Broadcast new challenge leaders to chat": false,
    "Update leaders on a timer (Recommended)": true,
    "Create and use Oxide groups for each challenge type": false,
    "Update timer (hours)": 1,
    "Maximum tags to display (Requires BetterChat)": 1,
    "Format of tags displayed (Requires BetterChat)": "[{TAG}]"
  },
  "Colors": {
    "Primary message color (hex)": "#ce422b",
    "Secondary message color (hex)": "#939393",
    "Title color (hex) (Requires BetterChat)": "#35585e",
    "UI Color - Background": {
      "Color (hex)": "#2b2b2b",
      "Alpha (0.0 - 1.0)": 0.98
    },
    "UI Color - Panel": {
      "Color (hex)": "#404141",
      "Alpha (0.0 - 1.0)": 1.0
    },
    "UI Color - Button": {
      "Color (hex)": "#393939",
      "Alpha (0.0 - 1.0)": 1.0
    }
  },
  "Version": {
    "Major": 2,
    "Minor": 0,
    "Patch": 45
  }
}