Anzac Day in nsw_au

When i set options to  ['au_nsw', :observed] eg:
`Holidays.between(Date.parse('2021-01-01'), Date.parse('2021-12-31'), 'au_nsw', :observed)`

I get ANZAC Day repeated.  both the formal (Sunday 2021-04-25) and observed (Monday 2020-04-26)
It seems to be the only nsw_au holiday to have this problem