Wrong result with IN list length reaching IN_PREDICATE_CONVERSION_THRESHOLD

--source include/have_sequence.inc

CREATE TABLE t (a INT PRIMARY KEY);

INSERT INTO t SELECT seq FROM seq_1_to_30;

ANALYZE TABLE t PERSISTENT FOR ALL;

SET IN_PREDICATE_CONVERSION_THRESHOLD=4;

SELECT a FROM t WHERE a IN ( 1, 1, 2, 194 );

SET IN_PREDICATE_CONVERSION_THRESHOLD=100;

SELECT a FROM t WHERE a IN ( 1, 1, 2, 194 );

drop table t;

SET IN_PREDICATE_CONVERSION_THRESHOLD=4;

SELECT a FROM t WHERE a IN ( 1, 1, 2, 194 );

a

1

1

2

SET IN_PREDICATE_CONVERSION_THRESHOLD=100;

SELECT a FROM t WHERE a IN ( 1, 1, 2, 194 );

a

1

2

explain extended SELECT a FROM t WHERE a IN ( 1, 1, 2, 194 );

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	4	100.00	

1	PRIMARY	t	eq_ref	PRIMARY	PRIMARY	4	tvc_0._col_1	1	100.00	Using index

3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

Warnings:

Note	1003	/* select#1 */ select `test`.`t`.`a` AS `a` from (values (1),(1),(2),(194)) `tvc_0` join `test`.`t` where `test`.`t`.`a` = `tvc_0`.`_col_1`