JSON_TABLE: Illegal mix of collations upon executing PS once, or SP/function twice

SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

PREPARE stmt FROM "

SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

";

EXECUTE stmt;

MariaDB [test]> SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

+------+

| a    |

+------+

| 2    |

+------+

1 row in set (0.001 sec)

MariaDB [test]> PREPARE stmt FROM "

    "> SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

    "> ";

Query OK, 0 rows affected (0.001 sec)

Statement prepared

MariaDB [test]> EXECUTE stmt;

ERROR 1267 (HY000): Illegal mix of collations (koi8u_general_ci,IMPLICIT) and (eucjpms_japanese_ci,IMPLICIT) for operation '='

SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

CREATE OR REPLACE PROCEDURE pr()

SELECT * FROM JSON_TABLE (CONVERT('[1,2]' USING koi8u), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt1 NATURAL JOIN JSON_TABLE (CONVERT('[2,3]' USING eucjpms), '$[*]' COLUMNS(a CHAR(8) PATH '$')) AS jt2;

CALL pr();

CALL pr();

MariaDB [test]> CALL pr();

+------+

| a    |

+------+

| 2    |

+------+

1 row in set (0.002 sec)

Query OK, 0 rows affected (0.002 sec)

MariaDB [test]> CALL pr();

ERROR 1267 (HY000): Illegal mix of collations (koi8u_general_ci,IMPLICIT) and (eucjpms_japanese_ci,IMPLICIT) for operation '='