Unexpected Results by join_cache_incremental

CREATE TABLE t0(c0 CHAR(100), c1 FLOAT UNIQUE);

CREATE TABLE t1(c0 CHAR(100), c1 FLOAT UNIQUE);

CREATE TABLE t2(c0 CHAR(100), c1 FLOAT UNIQUE);

INSERT INTO t2 VALUES ('a', 1);

INSERT INTO t1 VALUES ('b', 2);

INSERT INTO t1 VALUES ('', 3);

INSERT INTO t0 VALUES ('', 4);

INSERT INTO t0 VALUES ('c', 5);

SET SESSION optimizer_switch = 'join_cache_incremental=on';

SELECT t1.c1 FROM t2 CROSS JOIN t1 ON TRUE RIGHT JOIN t0 ON t1.c0 IN (t1.c0 REGEXP t1.c0); -- {3}, {3}

SET SESSION optimizer_switch = 'join_cache_incremental=off';

SELECT t1.c1 FROM t2 CROSS JOIN t1 ON TRUE RIGHT JOIN t0 ON t1.c0 IN (t1.c0 REGEXP t1.c0); -- {3}, {NULL}