Are you sure that 1st character is a normal space (character code 32)?

declare @s1 char(10), @s2 char(10)

select @s1 = CHAR(160) + 'WDT' + CHAR(160)

select @s1, '[' + LTRIM(RTRIM(@s1)) + ']'

select @s2 = CHAR(32) + 'WDT' + CHAR(32)

select @s2, '[' + LTRIM(RTRIM(@s2)) + ']'