Query returns wrong results (while using CHARACTER SET utf8)

CREATE TABLE t1 (i1 int);

INSERT INTO t1 VALUES (NULL),(3),(8),(0),(2);

CREATE TABLE t2 (v1 varchar(10) CHARACTER SET utf8, KEY v1 (v1(3)));

INSERT INTO t2 VALUES  ('k'),('rid'),('f'),('x');

CREATE TABLE t3 (v1 varchar(10) CHARACTER SET utf8, l1 varchar(10), pk int NOT NULL PRIMARY KEY, i1 int , i2 int, KEY v1 (v1(3)));

INSERT INTO t3 VALUES ('measure','m',2,NULL,2),('o','k',3,1970208768,NULL);

CREATE TABLE t4 (v1 varchar(10) CHARACTER SET utf8, l1 varchar(10), pk int NOT NULL PRIMARY KEY, i1 int , i2 int, KEY v1 (v1(3)));

INSERT INTO t4 VALUES ('e','we',1,-1,1),('n','o',2,4,4),('r','o',3,3,2),('o','secure',4,NULL,NULL),('t','e',8,-1,6);

SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2));

SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2)) WHERE (t4.i2 <=2);

MariaDB [test2]> SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2));

Empty set (0.001 sec)

MariaDB [test2]> SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2)) WHERE (t4.i2 <=2);

+---+

| 1 |

+---+

| 1 |

| 1 |

+---+

2 rows in set (0.001 sec)

MariaDB [test2]> explain extended SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2));

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+------------------------------------+

| id   | select_type | table | type   | possible_keys | key     | key_len | ref         | rows | filtered | Extra                              |

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+------------------------------------+

|    1 | PRIMARY     | t3    | index  | NULL          | PRIMARY | 4       | NULL        |    2 |   100.00 | Using index                        |

|    1 | PRIMARY     | t1    | ALL    | NULL          | NULL    | NULL    | NULL        |    5 |   100.00 | Using join buffer (flat, BNL join) |

|    1 | PRIMARY     | t4    | eq_ref | PRIMARY       | PRIMARY | 4       | test2.t1.i1 |    1 |   100.00 | Using where                        |

|    2 | SUBQUERY    | t2    | ALL    | NULL          | NULL    | NULL    | NULL        |    4 |   100.00 |                                    |

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+------------------------------------+

4 rows in set, 1 warning (0.001 sec)

Note (Code 1003): /* select#1 */ select 1 AS `1` from `test2`.`t3` join `test2`.`t1` left join `test2`.`t4` on(`test2`.`t4`.`pk` = `test2`.`t1`.`i1` and `test2`.`t1`.`i1` is not null) where <nop>(<in_optimizer>(`test2`.`t4`.`l1`,<max>(/* select#2 */ select max(`test2`.`t2`.`v1`) from `test2`.`t2`) > <cache>(convert(`test2`.`t4`.`l1` using utf8))))

MariaDB [test2]> explain extended SELECT 1 FROM t3 JOIN (t1 LEFT JOIN t4 ON t4.pk = t1.i1) ON ( t4.l1 < ANY (SELECT MAX(t2.v1) FROM t2)) WHERE (t4.i2 <=2);

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+-------------------------------------------------+

| id   | select_type | table | type   | possible_keys | key     | key_len | ref         | rows | filtered | Extra                                           |

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+-------------------------------------------------+

|    1 | PRIMARY     | t3    | index  | NULL          | PRIMARY | 4       | NULL        |    2 |   100.00 | Using index                                     |

|    1 | PRIMARY     | t1    | ALL    | NULL          | NULL    | NULL    | NULL        |    5 |   100.00 | Using where; Using join buffer (flat, BNL join) |

|    1 | PRIMARY     | t4    | eq_ref | PRIMARY       | PRIMARY | 4       | test2.t1.i1 |    1 |   100.00 | Using where                                     |

|    2 | SUBQUERY    | t2    | ALL    | NULL          | NULL    | NULL    | NULL        |    4 |   100.00 |                                                 |

+------+-------------+-------+--------+---------------+---------+---------+-------------+------+----------+-------------------------------------------------+

4 rows in set, 1 warning (0.000 sec)

Note (Code 1003): /* select#1 */ select 1 AS `1` from `test2`.`t3` join `test2`.`t1` join `test2`.`t4` where `test2`.`t4`.`pk` = `test2`.`t1`.`i1` and `test2`.`t4`.`i2` <= 2 and <nop>(<in_optimizer>(`test2`.`t4`.`l1`,<max>(/* select#2 */ select max(`test2`.`t2`.`v1`) from `test2`.`t2`) > <cache>(convert(`test2`.`t4`.`l1` using utf8))))