MariaDB 10.11.9 Server (Docker Container) crashes on a simple query

SELECT * FROM (

    (

        SELECT MAX(`dateCreated`) AS `latestDate`, A.* FROM (

            SELECT E.`empNo` AS `empNo`, E.`terminationId` AS `empTerminationId`, CR.`requestId`, CR.`dateCreated`

            FROM `ClaimRequest` CR INNER JOIN `Employee` E ON (CR.`empNo` = E.`empNo`)

            LIMIT 18446744073709551615

        ) AS A

        GROUP BY `requestId`

    )

    UNION

    (

        SELECT (`dateCreated`) AS `latestDate`, B.* FROM (

            SELECT E.`empNo` AS `empNo`, E.`terminationId` AS `empTerminationId`, CR.`requestId`, CR.`dateCreated`

            FROM `ClaimRequest` CR INNER JOIN `Employee` E ON (CR.`empNo` = E.`empNo`)

            LIMIT 18446744073709551615

        ) AS B

    )

) AS ED

WHERE

    CASE '1'

        WHEN 1 THEN `empTerminationId` IS NULL

        WHEN 2 THEN TRUE

        ELSE `empTerminationId` IS NOT NULL

    END;