ios - NSDateFormatter return nil from specific dates -

i'm having trouble nsdateformatter returns nil specific dates like, october 16, 2016 | october 15, 2017 | october 21, 2018 ...

i try date patterns: yyyy/mm/dd, mm/dd/yyyy, dd/mm/yyyy return nil.

any idea?

are living in brazil?

on these 3 particular dates daylight saving time changes in brazil 0:00 1:00.

since 0:00 not exist date nil.