Accept=1 may show incorrect value for NULL column in CONNECT TBL

CREATE TABLE q (

  id INT NOT NULL

) ENGINE=CONNECT TABLE_TYPE=CSV;

Query OK, 0 rows affected, 1 warning (0.02 sec)

Warning (Code 1105): No file name. Table will use q.csv

INSERT INTO q VALUES(1),(2),(3);

Query OK, 3 rows affected (0.00 sec)

Records: 3  Duplicates: 0  Warnings: 0

CREATE TABLE w (

  id INT NOT NULL, 

  m char (10)

) ENGINE=Innodb;

Query OK, 0 rows affected (0.12 sec)

INSERT INTO w VALUES(1,'a'),(2,'b'),(3,'c');

Query OK, 3 rows affected (0.01 sec)

Records: 3  Duplicates: 0  Warnings: 0

create table rt1(

id int not null,

m char(10)

)engine=connect  table_type= TBL table_list='q,w,q', option_list='Accept=1';

Query OK, 0 rows affected (0.02 sec)

select * from rt1;

+----+------+

| id | m    |

+----+------+

|  1 |      |

|  2 |      |

|  3 |      |

|  1 | a    |

|  2 | b    |

|  3 | c    |

|  1 | c    |

|  2 | c    |

|  3 | c    |

+----+------+

9 rows in set (0.00 sec)