Product search return results with score value as null

Rest Product Search using, V1/search endpoint with ‘quick_search_container’ searchCriteria always resurn product with null score value. Any idea?

Sample Request

/V1/search?searchCriteria[requestName]=quick_search_container&
searchCriteria[filterGroups][0][filters][0][field]=search_term&searchCriteria[filterGroups][0][filters][0][value]=Bag

Sample Response

{
  "items": [
    {
      "id": 6438,
      "custom_attributes": [
        {
          "attribute_code": "_score",
          "value": null
        }
      ]
    },
....
}