Wrong result with optimize_join_buffer_size=on on query with LEFT JOINs and constant table

CREATE TABLE t1 (f1 INT) ENGINE=MyISAM;

INSERT INTO t1 VALUES (4),(5),(8),(4),(1),(4),(8),(6),(4),(9),(2),(10),(9);

CREATE TABLE t2 (f2 INT) ENGINE=MyISAM;

INSERT INTO t2 VALUES (1),(2);

CREATE TABLE t3 (f3 INT) ENGINE=MyISAM;

INSERT INTO t3 VALUES (10);

CREATE TABLE t4 (f4 INT) ENGINE=MyISAM;

ANALYZE TABLE t1, t2, t3, t4;

set optimizer_switch = 'optimize_join_buffer_size=off';

SELECT f3 FROM t1 LEFT JOIN ( t2 LEFT JOIN t3 ON f2 = f3 INNER JOIN t4 ) ON f1 = f2;

set optimizer_switch = 'optimize_join_buffer_size=on';

SELECT f3 FROM t1 LEFT JOIN ( t2 LEFT JOIN t3 ON f2 = f3 INNER JOIN t4 ) ON f1 = f2;

# Cleanup

DROP TABLE t1, t2, t3, t4;

f3

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

f3

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

10

NULL