BUG: Wrong order and ambiguous start point for some period values

[GYHHAHA]

>>>pd.period_range('1350-01-01', '1350-01-02', freq='6h').sort_values()
PeriodIndex(['1350-01-01 23:00', '1350-01-01 05:00', '1350-01-01 11:00',
             '1350-01-01 17:00', '1350-01-02 23:00'],
            dtype='period[6H]', freq='6H')

Though sorted, '1350-01-01 23:00' still locates the first.

>>>pd.period_range('2150-01-01', '2150-01-02', freq='6h')
PeriodIndex(['2150-01-01 00:00', '2150-01-01 06:00', '2150-01-01 12:00',
             '2150-01-01 18:00', '2150-01-02 00:00'],
            dtype='period[6H]', freq='6H')

And why this starts at 00:00, but the former one starts at 23:00?

Thanks!

[phofl]

Hey, thanks for your report. This is actually a duplicate of #36294 and will be fixed with #36557

[GYHHAHA]

Hi, is this actually a duplication?

>>>pd.period_range('1400-01-01', '1400-01-02', freq='6h')
PeriodIndex(['1400-01-01 00:00', '1400-01-01 06:00', '1400-01-01 12:00',
             '1400-01-01 18:00', '1400-01-02 00:00'],
            dtype='period[6H]', freq='6H')

It seems to be normal though '1400' is also a pre epoch.

Thanks! @phofl

[phofl]

You are right, may be unrelated, but is fixed on master.

Sorry for the confusion: This is a duplicate of #36430 and was fixed by #36535

[GYHHAHA]

great

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