More results in field-restricted search than with all_fields

[kermitt2]

Something strange on my set of ~1000 documents: searching for "étude" with all fields gives 57 results while searching only in abstract gives 75 results.

versus

Corresponding (simplified) requests are as follow:

• without field restriction

{
  "fields": [
    "_id",
    "repositoryDocId"
  ],
  "query": {
    "bool": {
      "should": [],
      "must": [
        {
          "query_string": {
            "default_field": "_all",
            "query": "étude",
            "default_operator": "AND"
          }
        }
      ],
      "must_not": []
    }
  },
  "size": 1
}

• with field restriction

{
  "fields": [
    "_id",
    "repositoryDocId"
  ],
  "query": {
    "bool": {
      "should": [],
      "must": [
        {
          "query_string": {
            "fields": [
              "$teiCorpus.$teiHeader.$profileDesc.$abstract.$lang_en",
              "$teiCorpus.$teiHeader.$profileDesc.$abstract.$lang_fr",
              "$teiCorpus.$teiHeader.$profileDesc.$abstract.$lang_de"
            ],
            "query": "étude",
            "default_operator": "AND"
          }
        }
      ],
      "must_not": []
    }
  },
  "size": 10
}

Not really related: fields could also be written more compactly as follow (it was one reason of the lang post-fixed notation):

 "fields": [
   "$teiCorpus.$teiHeader.$profileDesc.$abstract.*"
 ],