Broken type checking for empty subqueries

Hello,

after upgrade from PG11 to PG14.8 the following statement started failing:

select
    a::BIGINT
FROM (
    SELECT
        '$maybeNumber'::VARCHAR AS a
    WHERE NOT '$maybeNumber' LIKE '%maybeNumber'
) AS foo;

Expected (as in PG11): The query should return empty result with one column.
Actual:  SQL Error [22P02]: ERROR: invalid input syntax for type bigint:
"$maybeNumber".

Where is a workaround that shows the behavior is quite non-stable.
Following passes normally while still using the same subquery with one
more empty result from another one:

select
    a::BIGINT
FROM (
    SELECT
        '$maybeNumber'::VARCHAR AS a
    WHERE NOT '$maybeNumber' LIKE '%maybeNumber'
    UNION
    SELECT '0' AS a WHERE false
) AS foo;

Thanks all for the great work you do on PG.
Marek Malevic