DateHistogram not working as expected

Mapping:

        {
          "test_2e311eff-97c0-4270-b254-0c43cd5f2acc": {
            "mappings": {
              "test_2e311eff-97c0-4270-b254-0c43cd5f2acc_type": {
                "properties": {
                  "2e311eff-97c0-4270-b254-0c43cd5f2accTableLevelStatsFieldInternalRule_Completeness": {
                    "type": "integer"
                  },
                  "_testile_row_id": {
                    "type": "keyword"
                  },
                  "date22": {
                    "type": "date",
                    "format": "yyyy-MM-dd||yyyy-MM-dd'T'HH:mm:ss||yyyy-MM-dd HH:mm:ss||yyyy-MM-dd'T'HH:mm:ss.SSS'Z'||HH:mm:ss||HH:mm:ss.SSS||date_optional_time||epoch_millis"
                  },
                  "datetime22": {
                    "type": "date",
                    "format": "yyyy-MM-dd||yyyy-MM-dd'T'HH:mm:ss||yyyy-MM-dd HH:mm:ss||yyyy-MM-dd'T'HH:mm:ss.SSS'Z'||HH:mm:ss||HH:mm:ss.SSS||date_optional_time||epoch_millis"
                  },
                  "time22": {
                    "type": "date",
                    "format": "yyyy-MM-dd||yyyy-MM-dd'T'HH:mm:ss||yyyy-MM-dd HH:mm:ss||yyyy-MM-dd'T'HH:mm:ss.SSS'Z'||HH:mm:ss||HH:mm:ss.SSS||date_optional_time||epoch_millis"
                  }
                }
              }
            }
          }
        }

Data in index

{
              "_testile_row_id": "1",
              "time22": "10:00:00",
              "datetime22": "2017-09-01T10:00:00"
            }
          },
          {
            "_index": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc",
            "_type": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc_type",
            "_id": "9ZoLUGsBn7EFIldnql5B",
            "_score": 1,
            "_source": {
              "_testile_row_id": "2",
              "time22": "11:09:00",
              "datetime22": "2017-09-02T22:00:00",
              "date22": null
            }
          },
          {
            "_index": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc",
            "_type": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc_type",
            "_id": "9poLUGsBn7EFIldnql5B",
            "_score": 1,
            "_source": {
              "_testile_row_id": "3",
              "time22": "03:09:00",
              "datetime22": "2017-09-02T10:00:00",
              "date22": "2016-09-01"
            }
          },
          {
            "_index": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc",
            "_type": "test_2e311eff-97c0-4270-b254-0c43cd5f2acc_type",
            "_id": "95oLUGsBn7EFIldnql5B",
            "_score": 1,
            "_source": {
              "_testile_row_id": "4",
              "time22": "15:09:00",
              "datetime22": null,
              "date22": "2016-09-01"
            }
          }
        ]
      }
    }

Date histogram aggregation query:

GET test_2e311eff-97c0-4270-b254-0c43cd5f2acc/_search
    {
      "aggs": {
        "Histogram": {
          "date_histogram": {
            "field": "date22",
            "interval": 677376000,
            "offset": 0,
            "order": {
              "_key": "asc"
            },
            "keyed": false,
            "min_doc_count": 0
          }
        }
      }
    }

Response:

{
  "aggregations": {
    "Histogram": {
      "buckets": [
        {
          "key_as_string": "2016-08-31",
          "key": 1472615424000,
          "doc_count": 2
        },
        {
          "key_as_string": "2016-09-08",
          "key": 1473292800000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-09-15",
          "key": 1473970176000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-09-23",
          "key": 1474647552000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-10-01",
          "key": 1475324928000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-10-09",
          "key": 1476002304000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-10-17",
          "key": 1476679680000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-10-25",
          "key": 1477357056000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-11-01",
          "key": 1478034432000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-11-09",
          "key": 1478711808000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-11-17",
          "key": 1479389184000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-11-25",
          "key": 1480066560000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-12-03",
          "key": 1480743936000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-12-11",
          "key": 1481421312000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-12-18",
          "key": 1482098688000,
          "doc_count": 0
        },
        {
          "key_as_string": "2016-12-26",
          "key": 1482776064000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-01-03",
          "key": 1483453440000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-01-11",
          "key": 1484130816000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-01-19",
          "key": 1484808192000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-01-27",
          "key": 1485485568000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-02-03",
          "key": 1486162944000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-02-11",
          "key": 1486840320000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-02-19",
          "key": 1487517696000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-02-27",
          "key": 1488195072000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-03-07",
          "key": 1488872448000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-03-15",
          "key": 1489549824000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-03-23",
          "key": 1490227200000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-03-30",
          "key": 1490904576000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-04-07",
          "key": 1491581952000,
          "doc_count": 0
        }
      ]
    }
  }
}

First bucket should be 2016-09-01

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