ElasticSearch has_parent scoring problem

ES_HasParent_ScoringProblem_TEST

echo "Delete old data"
curl -XDELETE "http://localhost:9200/testindex"

echo "Create test index"
curl -XPUT "http://localhost:9200/testindex/" -d'
{
  "index": {
    "number_of_replicas": "0",
    "number_of_shards": "1"
  }
}'

echo "Create mapping for parent documents"
curl -XPUT "http://localhost:9200/testindex/_mapping/document" -d'
{
  "document": {
    "properties": {
      "title": {
        "type": "string"
      }
    }
  }
}'

echo "Create mapping for child reviews"
curl -XPUT "http://localhost:9200/testindex/review/_mapping" -d'
{
  "review": {
    "_parent": {
      "type": "document"
    },
    "properties": {
      "comments": {
        "type": "string"
      }
    }
  }
}'

echo "Put 1 document and 1 child review to the index"
curl -XPUT "http://localhost:9200/testindex/document/1" -d'
{
  "title": "This is just a simple test title"
}'

curl -XPUT "http://localhost:9200/testindex/review/2?parent=1" -d'
{
  "comments": "Weird scoring example"
}'


echo "Test query 1:"
echo "Search for parent documents and also their child reviews"
echo "Scores are equal: 0.375 - it is fine!"

curl -XGET "http://localhost:9200/testindex/document,review/_search" -d'
{
  "explain": false,
  "query": {
    "bool": {
      "must": [
        {
          "dis_max": {
            "queries": [
              {
                "query_string": {
                  "query": "simple",
                  "fields": [
                    "document.title"
                  ]
                }
              },
              {
                "has_parent": {
                  "parent_type": "document",
                  "score_type": "score",
                  "query": {
                    "query_string": {
                      "query": "simple",
                      "fields": [
                        "document.title"
                      ]
                    }
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}'

echo "Test query 2:"
echo "The above query, but having it twice and connected with BOOL query"
echo "The scores of the two results should be the same, but we receive different scores"
echo "The problem seems that the queryNorm calculated differently for the has_parent parts..."

curl -XGET "http://localhost:9200/testindex/document,review/_search" -d'
{
  "explain": false,
  "query": {
    "bool": {
      "must": [
        {
          "dis_max": {
            "queries": [
              {
                "query_string": {
                  "query": "simple",
                  "fields": [
                    "document.title"
                  ]
                }
              },
              {
                "has_parent": {
                  "parent_type": "document",
                  "score_type": "score",
                  "query": {
                    "query_string": {
                      "query": "simple",
                      "fields": [
                        "document.title"
                      ]
                    }
                  }
                }
              }
            ]
          }
        },
        {
          "dis_max": {
            "queries": [
              {
                "multi_match": {
                  "query": "simple",
                  "fields": [
                    "document.title"
                  ]
                }
              },
              {
                "has_parent": {
                  "parent_type": "document",
                  "score_type": "score",
                  "query": {
                    "multi_match": {
                      "query": "simple",
                      "fields": [
                        "document.title"
                      ]
                    }
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}'