Check-Constraint works on Windows 10 Pro x64 with MariaDB 10.4.12, but not on Debian 9 (backports kernel) on version 10.1.48-MariaDB-0+deb9u2

SET SQL_NOTES = 0;

CREATE DATABASE IF NOT EXISTS `pf_server`;

USE `pf_server`;

DROP TABLE IF EXISTS `clientdb_mapping`;

CREATE TABLE IF NOT EXISTS `clientdb_mapping` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `expected_hash` varchar(60) DEFAULT NULL,

  `identify_hash` varchar(60) DEFAULT NULL,

  CHECK (

    CASE

      WHEN expected_hash IS NULL THEN identify_hash IS NULL

    END

  ),

  CHECK (

    CASE

      WHEN expected_hash IS NOT NULL

        AND identify_hash IS NOT NULL THEN expected_hash = identify_hash

    END

  ),

  `db_name` varchar(100) NOT NULL,

  `db_version` varchar(25) NOT NULL DEFAULT '1.1.1',

  `allnodes` int(11) NOT NULL DEFAULT '9999',

  `licensedate` date NOT NULL DEFAULT '2099-01-01',

  `licensedatenodes` date NOT NULL DEFAULT '2099-01-01',

  `timestamp` datetime DEFAULT CURRENT_TIMESTAMP,

  PRIMARY KEY (`id`),

  UNIQUE KEY `identify_hash` (`identify_hash`)

) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

SET SQL_NOTES = 1;