Boost on child is not changing score in v7.2

hi,

We are in the process of upgrading from v5.5.1 to v7.2.0, running on Windows 2012 (running JRE 1.8.0_231). So we are trying out the replacement of parent/child mapping type with the new join field. In existing app, we have queries which provide query time boost, based on matching child records.

I tried a simple query to retrieve parent based on child. This returns only 1 record. However, if I use boost option, the score is not changing. Its still returning score as 1. However, in v5.5.1, the score changes to 100, when I use boost. Is this a bug? Should I report this in GitHub? Please let me know.

GET myindex/_search
{
  "query": {
    "has_child": {
      "type": "childtype",
      "query": {
        "terms": {
          "somefield": ["somevalue"]
        }
      },
      "boost" : 100
    }
  }
}

Thanks!

Just to add, using score_mode also does not make a difference to score. Only if I use function_score, then only score is reflecting the value from boost. Else, its based on default _score.