Score_ в ElasticSearch безболезненный скрипт всегда возвращается 1

Question

Я считаю, что параметр _score должен возвращать текущий показатель релевантности документа, но в моей ситуации он всегда возвращает 1. Это может быть связано с использованием только пользовательских функций оценки?

Это мой JSON-запрос:

{
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "path": "skills",
            "score_mode": "sum",
            "query": {
              "function_score": {
                "boost_mode": "replace",
                "query": {
                  "match": {
                    "skills.ext_id": "1394"
                  }
                },
                "functions": [
                  {
                    "field_value_factor": {
                      "field": "skills.score",
                      "missing": 0
                    }
                  }
                ]
              }
            }
          }
        }
      ],
      "should": [
        {
          "function_score": {
            "boost_mode": "replace",
            "query": {
              "match_all": {}
            },
            "functions": [
              {
                "script_score": {
                  "script": {
                    "source": "_score"
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}

И это объяснение из запроса:

{"value"=>116.0,
 "description"=>"sum of:",
 "details"=>
  [{"value"=>115.0,
    "description"=>"Score based on 1 child docs in range from 4574 to 4622, best match:",
    "details"=>
     [{"value"=>115.0,
       "description"=>"sum of:",
       "details"=>
        [{"value"=>115.0,
          "description"=>"min of:",
          "details"=>
           [{"value"=>115.0, "description"=>"field value function: none(doc['skills.score'].value?:0.0 * factor=1.0)", "details"=>[]},
            {"value"=>3.4028235e+38, "description"=>"maxBoost", "details"=>[]}]},
         {"value"=>0.0,
          "description"=>"match on required clause, product of:",
          "details"=>
           [{"value"=>0.0, "description"=>"# clause", "details"=>[]},
            {"value"=>1.0, "description"=>"_type:__skills", "details"=>[]}]}]}]},
   {"value"=>1.0,
    "description"=>"min of:",
    "details"=>
     [{"value"=>1.0,
       "description"=>
        "script score function, computed with script:\"Script{type=inline, lang='painless', idOrCode='_score', options={}, params={}}\"",
       "details"=>[{"value"=>1.0, "description"=>"_score: ", "details"=>[{"value"=>1.0, "description"=>"*:*", "details"=>[]}]}]},
      {"value"=>3.4028235e+38, "description"=>"maxBoost", "details"=>[]}]}]}