Wrong result when query run as a prepared statement

create table t1 (t1a int, t1b int, t1c int) engine=myisam;

insert into t1 values (1,1,1),(2,2,2);

create table t2 (t2a int, t2b int, t2c int) engine=myisam;

insert into t2 values (1,1,1),(2,2,2),(3,3,3);

select * from t2 where t2a in

(

  select t1a from t1

    group by (select t1a > t2b) order by t1a

);

t2a	t2b	t2c

1	1	1

2	2	2

t2a	t2b	t2c

1	1	1