Usar HashBytes no SQL Server retorna resultados diferentes do banco de dados

declare @str1 as varchar(10)
declare @str2 as nvarchar(10)

set @str1 = '123456'
set @str2 = '123456'

select
  hashbytes('md5', @str1) as 'varchar',
  hashbytes('md5', @str2) as 'nvarchar'

varchar                             nvarchar
0xE10ADC3949BA59ABBE56E057F20F883E  0xCE0BFD15059B68D67688884D7A3D3E8C