ES Query that returns some empty hits

example.json

{ "a" : {
    "b" : {
      "c": {
        "d":{
          "first" : [
            {"e": {
                "f": {
                  "second" : [
                    {"message": "Nobody expects the Spanish inquisition!"}
                    ]
                }
              }
            },
            {"e": {
                "f": null
              }
            }
            ]
        }
      }
    }
  }
}










"registryactivities" : {
                                "keyOpened" : null, 

gistfile1.txt

¨{
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "path": "a.b.c.d.first",
            "query": {
              "nested": {
                "path": "a.b.c.d.first.e.f.second",
                "query": {
                  "bool": {
                    "filter": [
                      {
                        "term": {
                          "a.b.c.d.first.e.f.second.message": "Nobody expects the Spanish inquisition!"
                        }
                      }
                    ]
                  }
                }
              }
            }
          }
        }
      ]
    }
  },
  "inner_hits": {
    "kids0": {
      "path": {
        "a.b.c.d.first": {
          "size" : 1,
          "_source": false, 
          "inner_hits": {
            "kids0": {
              "path": {
                "a.b.c.d.first.e.f.second": {
                  "size" : 1,
                  "_source": [
                    "message",
                    "bla",
                    "blub"
                  ],
                  "query": {
                    "bool": {
                      "filter": [
                        {
                          "term": {
                            "a.b.c.d.first.e.f.second.message": "Nobody expects the Spanish inquisition!"
                          }
                        }
                      ]
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}