Akka Cluster all seed node shutdown

[park]

Hi, all
we use akka 2.5 version and setting cluster.
under is config example

akka {
  #loglevel = "DEBUG"

  extensions = ["com.romix.akka.serialization.kryo.KryoSerializationExtension$","akka.cluster.client.ClusterClientReceptionist"]

  actor {
    provider = "cluster"

    default-dispatcher {
      type = Dispatcher
      executor = "fork-join-executor"
      fork-join-executor {
        parallelism-min = 8
        parallelism-factor = 0.5
        parallelism-max = 32
      }
      # Throughput defines the number of messages that are processed in a batch before the thread is returned to the pool.
      throughput = 20
      # Throughput deadline for Dispatcher, set to 0 or negative for no deadline
      throughput-deadline-time = 500ms
    }
    kryo  {
      type = "graph"
      idstrategy = "default"
      serializer-pool-size = 16
      buffer-size = 4096
      max-buffer-size = -1
      use-manifests = true
      post-serialization-transformations = "off"
      implicit-registration-logging = false
      kryo-trace = false
    }

    serializers {
      java = "akka.serialization.JavaSerializer"
      kryo = "com.romix.akka.serialization.kryo.KryoSerializer"
    }

    serialization-bindings {
      "java.io.Serializable" = none
      "com.gamevilcom2us.hive.notification.push.data.domain.processing.Letter" = kryo
      "com.gamevilcom2us.hive.notification.push.data.domain.processing.Mail" = kryo
    }
  }

  remote {
    use-dispatcher = akka.actor.cluster-dispatcher

    use-passive-connections = off

    log-remote-lifecycle-events = off
    maximum-payload-bytes = 4194304 bytes

    netty {
      tcp {
        hostname = "localhost"
        port = {portNumber}
        maximum-frame-size = 4194304b
      }

      # (I&O) Used to configure the number of I/O worker threads on server sockets
      server-socket-worker-pool {
        pool-size-min = 8
        pool-size-factor = 1.0
        pool-size-max = 256
      }

      # (I&O) Used to configure the number of I/O worker threads on client sockets
      client-socket-worker-pool {
        pool-size-min = 8
        pool-size-factor = 1.0
        pool-size-max = 256
      }
    }

    watch-failure-detector {
      threshold = 12
      heartbeat-interval = 15s
      acceptable-heartbeat-pause = 3s
    }

    transport-failure-detector {
      heartbeat-interval = 15s
      acceptable-heartbeat-pause = 30s
    }
  }

  coordinated-shutdown.terminate-actor-system = on

  cluster {
    use-dispatcher = akka.actor.cluster-dispatcher


    seed-nodes = [
      "akka.tcp://test-service@localhost:2551",
      "akka.tcp://test-service@localhost:2552",
      "akka.tcp://test-service@localhost:2553",
      "akka.tcp://test-service@localhost:2554",
      "akka.tcp://test-service@localhost:2555",
      "akka.tcp://tset-service@localhost:2556"
    ]



    pub-sub {
      routing-logic = round-robin
      gossip-interval = 15s
    }

    shutdown-after-unsuccessful-join-seed-nodes = 45s
    #shutdown-after-unsuccessful-join-seed-nodes = off
	  #run-coordinated-shutdown-when-down = off

    receptionist {
      name = receptionist
      use-dispatcher = akka.actor.cluster-dispatcher

      response-tunnel-receive-timeout = 60s
      heartbeat-interval = 15s
      acceptable-heartbeat-pause = 3s
      failure-detection-interval = 5s
    }

    client {
      initial-contacts = [
        "akka.tcp://test-service@localhost:2551/system/receptionist",
        "akka.tcp://test-service@localhost:2552/system/receptionist",
        "akka.tcp://test-service@localhost:2553/system/receptionist",
        "akka.tcp://test-service@localhost:2554/system/receptionist",
        "akka.tcp://test-service@localhost:2555/system/receptionist",
        "akka.tcp://test-service@localhost:2556/system/receptionist"
      ]

      establishing-get-contacts-interval = 7s
      heartbeat-interval = 15s
      acceptable-heartbeat-pause = 9s
    }
  }

  # Akka Streams Kafka Configuration
  kafka {

    # Kafka Consumer
    consumer {
      server-list = "localhost:9092"
      poll-interval = 250ms
	  poll-timeout = 5s
	  stop-timeout = 30s
      close-timeout = 20s
      commit-timeout = 30s
      commit-time-warning = 5s
      wait-close-partition = 5s
      wakeup-debug = true

      kafka-clients {
        enable.auto.commit = true
      }

      # Consumers
      test {
        group-id = "test-service-group"
        client-id = "test-daemon-reload-consumer"
        auto-offset-reset = "earliest"
        topic = "test-daemon-reload"
        parallelism = 1
      }
    }

    # Kafka Producer
    producer {
      server-list = "localhost:9092"
      json {
        client-id = "test-json-producer"
        acks = "0"
      }
    }
  }
}

In our case If one node jvm was down, then all cluster node jvm was exit.
we want to if some node jvm was down then cluster member remove and cluster well working.
why all cluster node was shutdown??
plase help me. Thank you.