Triggers not executed following foreign key updates/deletes

This bug https://bugs.mysql.com/bug.php?id=11472 reported by Omer Barnir in 2005 affects Percona Server as well today! (and vanilla Oracle MySQL as well !!!). 

Quotation from his description and test case: 

USE test;

DROP TABLE IF EXISTS t1,t2;

CREATE TABLE t1 (id INT NOT NULL, col1 char(50), PRIMARY KEY (id)) ENGINE=INNODB;
CREATE TABLE t2 (id INT PRIMARY KEY, f_id INT, INDEX par_ind (f_id), col1 char(50),
FOREIGN KEY (f_id) REFERENCES t1(id) ON DELETE SET NULL) ENGINE=INNODB;

create trigger tr_t2 after update on t2
for each row set @counter=@counter+1;

insert into t1 values (1,'Department A');
insert into t1 values (2,'Department B');
insert into t1 values (3,'Department C');
insert into t2 values (1,2,'Emp 1');
insert into t2 values (2,2,'Emp 2');
insert into t2 values (3,2,'Emp 3');
insert into t2 values (4,2,'Emp 4');
insert into t2 values (5,2,'Emp 5');
set @counter=0;

select * from t1;
select * from t2;
select @counter;

delete from t1 where id=2;

select * from t1;
select * from t2;
select @counter;

update t2 set col1='Emp 5a' where id=5;
select * from t2;
select @counter;

drop table t2,t1;

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        • Note At this point 5 rows were updated in table t2, the value of

@count is expected to be '5' (each activation of the trigger
increases it by 1, and yet the value remained zero, indicating the
trigger was not executed.
The following shows that the trigger it self is executed when
table 't2' is updated directly: