Mob Arena stops when the boss spawns

I'm having issues with my mob arena plugin.

These are my current plugins:

Plugins (open) Plugins (close)

Plugins (49): §aWorldBorder§f, §aBalloonFiesta§f, §aBuycraft§f, §aMassiveCore§f, §aVault§f, §aMultiverse-Core§f, §aNoteBlockAPI§f, §aWhatIsIt§f, §aProtocolLib§f, §aPlayerVaults§f, §aVotifier§f, §aMobArena§f, §aGAListener§f, §aPwnFilter§f, §aServerShop-GUI§f, §aNoCheatPlus§f, §aWorldEdit§f, §aAdvancedTabList§f, §aMineplexChat§f, §aHealthBar§f, §aPermissionsEx§f, §aCommandWatcher§f, §aWorldGuard§f, §aHeroicDeathPlus§f, §aLottery§f, §aClaimLevels§f, §aCoreProtect§f, §aChopTree2§f, §aMultiverse-Downloader§f, §aClearLag§f, §aAreaShop§f, §aAutoAnnouncer§f, §aEssentials§f, §afloAuction§f, §aicJukeBox§f, §aLibsDisguises§f, §aMultiverse-Portals§f, §aSilkSpawners§f, §aCrateReloaded§f, §aChestShop§f, §aEssentialsChat§f, §amcMMO§f, §aKitPreview§f, §aEssentialsSpawn§f, §aMultiverse-NetherPortals§f, §aFactions§f, §aEnjinMinecraftPlugin§f, §aObsidianDestroyer§f, §aCombatLog

This is my mob arena config.yml

Config.yml (open) Config.yml (close)

# MobArena v0.96.8 - Config-file
# Read the Wiki for details on how to set up this file: http://goo.gl/F5TTc
# Note: You -must- use spaces instead of tabs!
global-settings:
enabled: true
allowed-commands: /list, /pl
update-notification: true
classes:
knight:
items: iron_sword 16:2, potion:8233:4, potion:8257:2
armor: iron_boots 0:1, iron_leggings 0:1, iron_chestplate 0:1, iron_helmet 0:1
heavy:
items: iron_axe 16:1, potion:8229:4, potion:8233:2, potion:8227:2
armor: iron_boots 0:3, iron_leggings 0:3, iron_chestplate 0:3, iron_helmet 0:3
Scout:
items: bow 51:1;48:2, iron_sword 19:1, potion:8258:1, potion:8226:2, potion:8267:1, potion:8270:2, arrow
armor: leather_boots 0:2, leather_leggings 0:2, leather_chestplate 0:2, leather_helmet 0:2
Berserker:
items: iron_axe 16:4, potion:8233:4, potion:8257:2, potion:16428:16
armor: leather_boots 0:1, leather_leggings 0:1, leather_chestplate 0:1
Priest:
items: blaze_rod 19:2, potion:16453:32, potion:16419:4, potion:16393:2, potion:16417:1, potion:16430:1
armor: gold_boots 0:3, gold_leggings 0:3, gold_chestplate 0:3, gold_helmet 0:3
Mage:
items: blaze_rod 17:5, potion:16420:8, potion:16421:8, potion:16428:32, potion:16456:16, potion:8257:2, potion:8225:1
armor: leather_boots 7:3, leather_leggings 7:3, leather_chestplate 7:3
Marksmen:
items: bow 51:1;48:4, gold_sword 19:1, potion:16421:3, potion:16427:1, potion:16430:1, arrow
armor: leather_boots 4:3, leather_leggings 4:3, leather_chestplate 4:3, leather_helmet 4:3
Assassin:
items: iron_sword 16:5, bow 51:1;48:5, potion:8258:1, potion:8229:1, potion:8233:4, potion:16420:16, arrow
armor: ''
Pyrotechnics:
items: blaze_rod 19:2, potion:8233:4, potion:16428:32, tnt:64, tnt:64
armor: chainmail_boots 3:4, chainmail_leggings 3:4, chainmail_chestplate 3:4, chainmail_helmet 3:4
DMage:
items: blaze_rod 17:5;20:2, potion:16428:64, potion:16421:64, potion:16420:32, potion:16456:16, potion:16451:2, potion:16449:2, potion:16417:2, tnt:32
armor: leather_boots 0:2;7:3, leather_leggings 0:2;7:3, leather_chestplate 0:2;7:3
DKnight:
items: iron_sword 16:4;20:1, potion:8257:8, potion:8265:4, tnt:32
armor: iron_boots 0:3, iron_leggings 0:3, iron_chestplate 0:3, iron_helmet 0:3
DBerserker:
items: iron_axe 16:5, potion:16428:32, potion:8233:8, potion:8257:8, tnt:32
armor: chainmail_boots 0:2, chainmail_leggings 0:2, chainmail_chestplate 0:2, chainmail_helmet 0:2
DScout:
items: bow 51:1;48:4, iron_sword 19:1;16:2, potion:8226:4, potion:8258:1, potion:8267:1, potion:8238:1, arrow, tnt:32
armor: leather_boots 0:4, leather_leggings 0:4, leather_chestplate 0:4, leather_helmet 0:4
DPriest:
items: blaze_rod 19:2;20:2, potion:16421:64, potion:16456:16, potion:16449:4, potion:16386:2, potion:16451:2, potion:16430:1, tnt:32
armor: gold_boots 0:4, gold_leggings 0:4, gold_chestplate 0:4, gold_helmet 0:4
DMarksmen:
items: bow 51:1;49:1;48:5, gold_sword 16:2;19:1, potion:16421:8, potion:8267:1, potion:8238:1, arrow, tnt:32
armor: leather_boots 0:4, leather_leggings 0:4, leather_chestplate 0:4, leather_helmet 0:4
DPyrotechnics:
items: blaze_rod 19:2;20:2, potion:16428:64, potion:8233:8, potion:8257:2, tnt:64, tnt:64, tnt:64
armor: chainmail_boots 0:4, chainmail_leggings 0:4, chainmail_chestplate 0:4, chainmail_helmet 0:4
DHeavy:
items: diamond_axe 16:1, potion:16421:8, potion:8233:2, potion:8257:2, potion:8259:2, tnt:32
armor: diamond_boots 0:4, diamond_leggings 0:4, diamond_chestplate 0:4, diamond_helmet 0:4
DAssassin:
items: iron_sword 16:5, bow 51:1;48:5, arrow, potion:16428:64, potion:16420:32, potion:16421:8, potion:8258:4, potion:8238:2, tnt:32
armor: leather_boots 0:1, leather_leggings 0:1, leather_chestplate 0:1, leather_helmet 0:1
Reaper:
items: iron_hoe 16:3, potion:16428:64, potion:16420:32, potion:16456:16, potion:8270:2, fireball:50
armor: leather_boots 0:1;7:3, leather_leggings 0:1;7:3, leather_chestplate 0:1;7:3, skull_item:1:1 0:2
helmet: skull_item:1:1 0:2
DReaper:
items: iron_hoe 16:5;20:2, potion:16428:64, potion:16428:64, potion:16420:64, potion:16456:16, potion:8270:2, fireball:50, fireball:50, tnt:32
armor: leather_boots 0:3;7:3, leather_leggings 0:3;7:3, leather_chestplate 0:3;7:3, skull_item:1:1 0:4
helmet: skull_item:1:1 0:4
arenas:
arena:
settings:
world: map
enabled: true
protect: true
entry-fee: $100
clear-wave-before-next: false
clear-boss-before-next: false
clear-wave-before-boss: false
soft-restore: false
soft-restore-drops: false
require-empty-inv-join: false
require-empty-inv-spec: false
hellhounds: true
pvp-enabled: false
monster-infight: false
allow-teleporting: false
spectate-on-death: false
auto-respawn: true
share-items-in-arena: false
min-players: 0
max-players: 10
max-join-distance: 0
first-wave-delay: 5
wave-interval: 25
final-wave: 0
monster-limit: 300
monster-exp: false
keep-exp: true
food-regen: true
lock-food-level: true
player-time-in-arena: world
auto-ignite-tnt: true
auto-start-timer: 0
start-delay-timer: 0
auto-ready: false
use-class-chests: false
display-waves-as-level: false
display-timer-as-level: false
use-scoreboards: true
isolated-chat: false
global-join-announce: false
global-end-announce: false
show-death-messages: true
waves:
recurrent:
def1:
type: default
priority: 1
frequency: 1
monsters:
zombies: 10
skeletons: 10
spiders: 10
creepers: 10
wolves: 10
spec1:
type: special
priority: 2
frequency: 4
monsters:
powered-creepers: 10
zombie-pigmen: 10
angry-wolves: 10
blazes: 10
single:
swarm1:
type: swarm
wave: 6
monster: slime
amount: low
boss1:
type: boss
wave: 12
monster: cave_spider
health: high
abilities: arrows, root-target, throw-nearby
rewards:
waves:
every:
'3': $10
'5': $50
'10': $100
after:
'7': $50
'13': $150
'16': $200
'22': $250
'25': $300
'28': $350
'31': $450
'34': $550
'37': $700
'40': $800
'45': $1000
'50': $1200
'55': $1400
'60': $1600
'65': $1800
'70': $2000
'75': $2300
'80': $2500
'85': $2700
'95': $2900
'100': $3500
coords:
spawnpoints:
879,187,1107: 879.5,187,1107.5,0.0,0.0,map
884,186,1102: 884.5,186,1102.5,0.0,0.0,map
882,186,1095: 882.5,186,1095.5,0.0,0.0,map
884,186,1089: 884.5,186,1089.5,0.0,0.0,map
887,186,1084: 887.5,186,1084.5,0.0,0.0,map
879,187,1084: 879.5,187,1084.5,0.0,0.0,map
882,183,1081: 882.5,183,1081.5,0.0,0.0,map
873,183,1090: 873.5,183,1090.5,0.0,0.0,map
867,183,1091: 867.5,183,1091.5,0.0,0.0,map
862,183,1095: 862.5,183,1095.5,0.0,0.0,map
865,183,1100: 865.5,183,1100.5,0.0,0.0,map
870,183,1100: 870.5,183,1100.5,0.0,0.0,map
877,183,1104: 877.5,183,1104.5,0.0,0.0,map
882,183,1110: 882.5,183,1110.5,0.0,0.0,map
885,183,1113: 885.5,183,1113.5,0.0,0.0,map
862,183,1091: 862.5,183,1091.5,0.0,0.0,map
861,183,1089: 861.5,183,1089.5,0.0,0.0,map
857,183,1086: 857.5,183,1086.5,0.0,0.0,map
853,183,1081: 853.5,183,1081.5,0.0,0.0,map
850,183,1078: 850.5,183,1078.5,0.0,0.0,map
862,183,1101: 862.5,183,1101.5,0.0,0.0,map
858,183,1105: 858.5,183,1105.5,0.0,0.0,map
853,183,1110: 853.5,183,1110.5,0.0,0.0,map
850,183,1113: 850.5,183,1113.5,0.0,0.0,map
877,183,1086: 877.5,183,1086.5,0.0,0.0,map
886,183,1077: 886.5,183,1077.5,0.0,0.0,map
891,188,1081: 891.5,188,1081.5,0.0,0.0,map
891,188,1088: 891.5,188,1088.5,0.0,0.0,map
891,188,1109: 891.5,188,1109.5,0.0,0.0,map
843,188,1109: 843.5,188,1109.5,0.0,0.0,map
844,189,1101: 844.5,189,1101.5,0.0,0.0,map
867,185,1085: 867.5,185,1085.5,0.0,0.0,map
876,185,1096: 876.5,185,1096.5,0.0,0.0,map
868,185,1104: 868.5,185,1104.5,0.0,0.0,map
858,185,1096: 858.5,185,1096.5,0.0,0.0,map
843,189,1095: 843.5,189,1095.5,0.0,0.0,map
842,192,1105: 842.5,192,1105.5,0.0,0.0,map
893,192,1086: 893.5,192,1086.5,0.0,0.0,map
896,190,1111: 896.5,190,1111.5,0.0,0.0,map
884,191,1124: 884.5,191,1124.5,0.0,0.0,map
839,190,1080: 839.5,190,1080.5,0.0,0.0,map
851,191,1067: 851.5,191,1067.5,0.0,0.0,map
containers: {}
p1: 832,179,1059,0.0,0.0,map
p2: 904,202,1131,0.0,0.0,map
lobby: 839.5,195,1096.5,-87.68,0.0,map
spectator: 889.5,195,1117.5,-218.94,0.0,map
exit: 839.5,195,1096.5,-89.72,0.0,map
arena: 862.5,183,1101.5,-127.78,0.0,map
l1: 894,194,1090,0.0,0.0,map
l2: 899,199,1101,0.0,0.0,map
class-limits:
Archer: -1
Oddjob: -1
Chemist: -1
Tank: -1
Knight: -1
Knight+: -1
Berserker+: -1
Priest+: -1
Pyrotechnics+: -1
Heavy+: -1
Assassin+: -1

So what's happening, is when the Mob Arena reaches round 12 for the boss, the boss gets one shot by the player inside the arena and the waves stop.

What's wrong?
Thanks