Problem expanding replicas for _percolator

health

{
  "cluster_name" : "percolate",
  "status" : "yellow",
  "timed_out" : false,
  "number_of_nodes" : 3,
  "number_of_data_nodes" : 3,
  "active_primary_shards" : 3,
  "active_shards" : 9,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 4
}

results

{
  "_percolator" : {
    "settings" : {
      "index.number_of_shards" : "1",
      "index.number_of_replicas" : "4",
      "index.auto_expand_replicas" : "false"
    }
  }
}
{"ok":true}
{
  "_percolator" : {
    "settings" : {
      "index.number_of_shards" : "1",
      "index.number_of_replicas" : "6",
      "index.auto_expand_replicas" : "false"
    }
  }
}

set-replicas.sh

#!/bin/bash

curl -XGET rogue:9200/_percolator/_settings?pretty=true
echo
curl -XPUT rogue:9200/_percolator/_settings -d '
{
    "index" : {
        "number_of_replicas" : 6,
        "auto_expand_replicas" : false
    }
}'
echo
curl -XGET rogue:9200/_percolator/_settings?pretty=true
echo