Double negation changes the result of ANY subquery comparison

A double negation around an ANY subquery comparison changes the result of the expression.
The following two expressions should be logically equivalent:

5 <> ANY(SELECT 6)

and:

NOT (NOT (5 <> ANY(SELECT 6)))

However, MariaDB returns different results. The original expression returns 1, but the double-negated expression returns 0.
This violates the expected boolean identity NOT (NOT P) = P.

How to repeat

SELECT

  5 <> ANY(SELECT 6) AS orig,

  NOT (NOT (5 <> ANY(SELECT 6))) AS double_negated;

SELECT

  5 < ANY(SELECT 6) AS orig,

  NOT (NOT (5 < ANY(SELECT 6))) AS double_negated;

Observed result

orig  double_negated

1     0

orig  double_negated

1     0

Expected result

orig  double_negated

1     1

orig  double_negated

1     1