WHEN [Measures].[Issues created] >= 97 and [Measures].[Issues created] =< 100 then ‘Expected’
In your formula you mixed up the order, it should be <= not =<
You will then run in another error because you show a string in the THEN-case but a number in the ELSE-case. It should be both string or number.
Silly me, how could I not notice that?