Problem/Bug MobArena Help!

Hello, i have a problem with MobArena, The problem is that: I want every round 10 mobs of each appear as in "config.yml" but always begins MobArena, Spawn alone 3 or 4 mobs, I wish that every round Spawn 10 mobs each appear, anyone know how to do this?, Thanks!

Code:

arenas:
  default:
    settings:
      world: Spawn
      enabled: true
      protect: true
      entry-fee: ''
      clear-wave-before-next: true
      clear-boss-before-next: true
      clear-wave-before-boss: true
      soft-restore: false
      soft-restore-drops: false
      require-empty-inv-join: true
      require-empty-inv-spec: false
      hellhounds: false
      pvp-enabled: false
      monster-infight: false
      allow-teleporting: false
      spectate-on-death: false
      auto-respawn: true
      share-items-in-arena: true
      min-players: 0
      max-players: 8
      max-join-distance: 70
      first-wave-delay: 5
      wave-interval: 15
      final-wave: 0
      monster-limit: 100
      monster-exp: false
      keep-exp: true
      food-regen: false
      lock-food-level: true
      player-time-in-arena: world
      auto-ignite-tnt: false
      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
            baby_zombies: 10
        spec1:
          type: special
          priority: 2
          frequency: 4
          monsters:
            powered-creepers: 23
            zombie-pigmen: 23
            cave_spider: 23
            baby_pigman: 23
            blazes: 23
      single:
        swarm1:
          type: swarm
          wave: 9
          monster: zombie-pigmen
          amount: medium
        boss1:
          type: boss
          wave: 10
          monster: wither_skeleton
          health: high
          abilities: fire-aura, root-target, throw-nearby