Is there a bug of rightedge=False with resampling()

[G_will]

extract and modify some codes from samples/bidask-to-ohlc/bidask-to-ohlc.py:

resample ticks data to 1 minute bar data:

    data = btfeeds.GenericCSVData(
        dataname='../../datas/bidask2.csv',
        dtformat='%d/%m/%y',
        # tmformat='%H%M%S',  # already the default value
        # datetime=0,  # position at default
        time=1,  # position of time
        open=5,  # position of open
        high=5,
        low=5,
        close=5,
        volume=7,
        openinterest=-1,
        timeframe=bt.TimeFrame.Ticks)

    cerebro.resampledata(data,
                         timeframe=bt.TimeFrame.Minutes,
                         compression=1)

output:

2016-03-01 23:44:00,130.52,130.52,130.52,130.52,3000000.0
2016-03-01 23:50:00,130.51,130.55,130.55,130.55,3650000.0
2016-03-01 23:52:00,130.5,130.5,130.5,130.5,1200000.0
2016-03-01 23:53:00,130.495,130.495,130.495,130.495,1100000.0
2016-03-01 23:54:00,130.48,130.48,130.48,130.48,600000.0
2016-03-01 23:55:00,130.47,130.47,130.47,130.47,900000.0

It is right.

But, If I want to label data use starting boundary and set rightedge=False

    data = btfeeds.GenericCSVData(
        dataname='../../datas/bidask2.csv',
        dtformat='%d/%m/%y',
        # tmformat='%H%M%S',  # already the default value
        # datetime=0,  # position at default
        time=1,  # position of time
        open=5,  # position of open
        high=5,
        low=5,
        close=5,
        volume=7,
        openinterest=-1,
        timeframe=bt.TimeFrame.Ticks)

    cerebro.resampledata(data,
                         timeframe=bt.TimeFrame.Minutes,
                         compression=1,
                         rightedge=False)

and output:

2016-03-01 23:43:27,130.52,130.52,130.52,130.52,3000000.0
2016-03-01 23:49:27,130.51,130.55,130.55,130.55,3650000.0
2016-03-01 23:51:25,130.5,130.5,130.5,130.5,1200000.0
2016-03-01 23:52:27,130.495,130.495,130.495,130.495,1100000.0
2016-03-01 23:53:25,130.48,130.48,130.48,130.48,600000.0
2016-03-01 23:54:00,130.47,130.47,130.47,130.47,900000.0

It seems wrong, some date lebal was not at the starting boundary. I think it should be :

2016-03-01 23:43:00,130.52,130.52,130.52,130.52,3000000.0
2016-03-01 23:49:00,130.51,130.55,130.55,130.55,3650000.0
2016-03-01 23:51:00,130.5,130.5,130.5,130.5,1200000.0
2016-03-01 23:52:00,130.495,130.495,130.495,130.495,1100000.0
2016-03-01 23:53:00,130.48,130.48,130.48,130.48,600000.0
2016-03-01 23:54:00,130.47,130.47,130.47,130.47,900000.0

[G_will]

@backtrader

Is it a bug? or my using method is not correct?