wrong datetimemin datetimemax in explorer

[pat1]

import dballe

with dballe.Explorer("dballe_report_fixed.json") as newexplorer:
    print (newexplorer.stats)
    for cur in newexplorer.query_summary():
        print (cur["datetimemin"],cur["datetimemax"])

output:

python tmp.py|head
ExplorerStats(datetime_min=datetime.datetime(2017, 4, 18, 0, 0), datetime_max=datetime.datetime(2017, 4, 18, 23, 59, 50), count=22755)
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
2017-01-01 00:00:00 2017-01-01 00:00:00
...

explorer attached:
explorer.zip