Redis [question] cluster del-node on docker but the nodes.conf would not being cleaned

  i got a confused problem,i build four node on docker  to constitute a redis cluster ,  then  i delete a master node from this cluster,  i am sure all the anther nodes has forget this node; 
  but since i start up the exited node,  i would got following exceptions:

the restarted node think that it is in this cluster , and even could send message to the cluster

i might think that because of the file nodes.conf was uncleaned ;