Why am I losing addressability to my Common Table Expression

Exactly.

It's a use it or lose it scenario.

WITH CTE AS (
SELECT 'a' AS a
)

SELECT 'b'

SELECT *
  FROM CTE

Gives an error "Common table expression defined by not used".

WITH CTE AS (
SELECT 'a' AS a
)

SELECT *
  FROM CTE

SELECT *
  FROM CTE

The first select works, but the second gives the error "Invalid object name 'CTE'".

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