ES5.0A2: Highlighting and _all field

The terms "Palais" and "Louvre" are not highlighted in the appellation_courante field. They are in the commune field.

After some investigation it seems related to being include to _all field or not:
The fields are mapped differently:

"monument": {
  "include_in_all":false,
  "properties": {
        "appellation_courante": {
          "type": "text",
          "include_in_all": true,
          "analyzer": "french"
        },
        "commune": {
          "type": "text"
        },

Manually executing the query in Elasticsearch

No highlighting:

POST monument/_search
{
  "query": {
    "match": {
      "_all": "Palais du Louvre"
    }
  },
  "highlight": {"fields": {
    "appellation_courante":{}
  }
  }
}

POST monument/_search
{
  "query": {
    "query_string": {
      "query": "Palais du Louvre"
    }
  },
  "highlight": {"fields": {
    "appellation_courante":{}
  }
  }
}

Highlighting is OK:

POST monument/_search
{
  "query": {
    "match": {
      "appellation_courante": "Palais du Louvre"
    }
  },
  "highlight": {"fields": {
    "appellation_courante":{}
  }
  }
}

POST monument/_search
{
  "query": {
    "query_string": {
      "query": "appellation_courante:Palais du Louvre"
    }
  },
  "highlight": {"fields": {
    "appellation_courante":{}
  }
  }
}