index.query.parse.allow_unmapped_fields setting does not seem to allow unmapped fields in alias filters

allow_unmapped_fields.sh

# verify we are allowing unmapped fields
curl -s -XGET '/_nodes?pretty=true' | grep allow_unmapped
#              "allow_unmapped_fields" : "true"

# delete the index
curl -XDELETE 127.0.0.1:9200/test1

# create index with explicit mapping only for user field
curl -XPUT 127.0.0.1:9200/test1 -d '
{
  "mappings": {
    "type1": {
      "properties": {
        "user" : {
          "type": "string",
          "index": "not_analyzed"
        }
      }
    }
  }
}'

# try to create alias with filter on unmapped field
curl -XPOST 127.0.0.1:9200/_aliases -d '
{
  "actions": [
    {
      "add": {
        "index": "test1",
        "alias": "alias4",
        "filter": {
          "term": {
            "unknownfield": "kimchy"
          }
        }
      }
    }
  ]
}'

# {"error":"ElasticsearchIllegalArgumentException[failed to parse filter for alias [alias4]]; nested: QueryParsingException[[test1] Strict field resolution and no field mapping can be found for the field with name [unknownfield]]; ","status":400}