Some string functions in a virtual column lead the table corruption on @@max_allowed_packet change

SET GLOBAL max_allowed_packet=16777216*2;

KILL CONNECTION_ID();

CREATE OR REPLACE TABLE t1 (

  a VARCHAR(64),

  v INT GENERATED ALWAYS AS (LENGTH(REPEAT(a,16777216*2))),

  KEY(v)

) ENGINE=MyISAM;

INSERT INTO t1 (a) VALUES ('a');

SELECT * FROM t1;

KILL CONNECTION_ID();

SET GLOBAL max_allowed_packet=16777216;

KILL CONNECTION_ID();

CHECK TABLE t1;

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

| Table   | Op    | Msg_type | Msg_text                                                                     |

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

| test.t1 | check | error    | Checksum for key:  1 doesn't match checksum for records                      |

| test.t1 | check | Warning  | Result of repeat() was larger than max_allowed_packet (16777216) - truncated |

| test.t1 | check | error    | Corrupt                                                                      |

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