Join raises wrong result

[zimulala]

1. What did you do?

create table t(c1 int, c2 int);
create table t1(c1 int, c2 int);
insert into t values(1,1),(2,2);
insert into t1 values(2,3),(4,4);
select * from t left outer join t1 on t.c1 = t1.c1 where t.c1 = 1 or t1.c2 > 20;

2.What did you expect to see?
+------+------+------+------+
| c1 | c2 | c1 | c2 |
+------+------+------+------+
| 1 | 1 | NULL | NULL |
+------+------+------+------+

3.What did you see instead?
+------+------+------+------+
| c1 | c2 | c1 | c2 |
+------+------+------+------+
| 1 | 1 | NULL | NULL |
| 2 | 2 | NULL | NULL |
+------+------+------+------+