Strange date histogram facet behavior with ElasticSearch version 0.18.5

gistfile1.sh

curl -X PUT 'http://localhost:9200/articles/article/1?pretty=true' -d '{
    "title": "One",
    "some_date": "2000-01-01T00:00:00"
}'

# {
#   "ok" : true,
#   "_index" : "articles",
#   "_type" : "article",
#   "_id" : "1",
#   "_version" : 1
# }


curl -X PUT 'http://localhost:9200/articles/article/2?pretty=true' -d '{
    "title": "Two",
    "some_date": "2000-01-01T00:01:00"
}'

# {
#   "ok" : true,
#   "_index" : "articles",
#   "_type" : "article",
#   "_id" : "2",
#   "_version" : 1
# }



curl -X PUT 'http://localhost:9200/articles/article/3?pretty=true' -d '{
    "title": "Three",
    "some_date": "2000-01-01T00:02:00"
}'

# {
#   "ok" : true,
#   "_index" : "articles",
#   "_type" : "article",
#   "_id" : "3",
#   "_version" : 1
# }

curl 'http://localhost:9200/articles/article/_search?pretty=true' -d '{
    "query": {
        "match_all": {}
    }, 
    "facets": {
        "rollup": {
            "date_histogram": {
                "field": "some_date", 
                "interval": "minute",
                "time_zone": "America/New_York"
            }
        }
    }
}'

# {
#   "took" : 4,
#   "timed_out" : false,
#   "_shards" : {
#     "total" : 6,
#     "successful" : 6,
#     "failed" : 0
#   },
#   "hits" : {
#     "total" : 3,
#     "max_score" : 1.0,
#     "hits" : [ {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "3",
#       "_score" : 1.0, "_source" : {
#     "title": "Three",
#     "some_date": "2000-01-01T00:02:00"
# }
#     }, {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "1",
#       "_score" : 1.0, "_source" : {
#     "title": "One",
#     "some_date": "2000-01-01T00:00:00"
# }
#     }, {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "2",
#       "_score" : 1.0, "_source" : {
#     "title": "Two",
#     "some_date": "2000-01-01T00:01:00"
# }
#     } ]
#   },
#   "facets" : {
#     "rollup" : {
#       "_type" : "date_histogram",
#       "entries" : [ {
#         "time" : 946684800000,
#         "count" : 1
#       }, {
#         "time" : 946684860000,
#         "count" : 1
#       }, {
#         "time" : 946684920000,
#         "count" : 1
#       } ]
#     }
#   }
# }

curl 'http://localhost:9200/articles/article/_search?pretty=true' -d '{
    "query": {
        "match_all": {}
    }, 
    "facets": {
        "rollup": {
            "date_histogram": {
                "field": "some_date", 
                "interval": "minute"
            }
        }
    }
}'

# {
#   "took" : 2,
#   "timed_out" : false,
#   "_shards" : {
#     "total" : 6,
#     "successful" : 6,
#     "failed" : 0
#   },
#   "hits" : {
#     "total" : 3,
#     "max_score" : 1.0,
#     "hits" : [ {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "3",
#       "_score" : 1.0, "_source" : {
#     "title": "Three",
#     "some_date": "2000-01-01T00:02:00"
# }
#     }, {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "1",
#       "_score" : 1.0, "_source" : {
#     "title": "One",
#     "some_date": "2000-01-01T00:00:00"
# }
#     }, {
#       "_index" : "articles",
#       "_type" : "article",
#       "_id" : "2",
#       "_score" : 1.0, "_source" : {
#     "title": "Two",
#     "some_date": "2000-01-01T00:01:00"
# }
#     } ]
#   },
#   "facets" : {
#     "rollup" : {
#       "_type" : "date_histogram",
#       "entries" : [ {
#         "time" : 946684800000,
#         "count" : 1
#       }, {
#         "time" : 946684860000,
#         "count" : 1
#       }, {
#         "time" : 946684920000,
#         "count" : 1
#       } ]
#     }
#   }
# }