ON UPDATE CURRENT_TIMESTAMP may lead to data inconsistency

[zyguan]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

/* t */ drop table if exists t;
-- t >> 0 rows affected
/* t */ create table t (id int, val int, updated_at timestamp(0) not null default current_timestamp(0) on update current_timestamp(0), primary key (id, updated_at), key idx_updated_at (updated_at));
-- t >> 0 rows affected
/* t */ insert into t values (1, 10, '2023-06-10 22:30:00');
-- t >> 1 rows affected
/* t */ update t force index(primary) set val = 11 where updated_at = '2023-06-10 22:30:00';
-- t >> 1 rows affected
/* t */ admin check table t;
-- t >> E8134: data inconsistency in table: t, index: idx_updated_at, col: updated_at, handle: "{1, 1851072800110936064}", index-values:"KindMysqlTime 2023-06-10 22:33:27" != record-values:"KindMysqlTime 2023-06-10 22:30:00", compare err:<nil>

2. What did you expect to see? (Required)

No error reported by admin-check.

3. What did you see instead (Required)

Found data inconsistency.

4. What is your TiDB version? (Required)

v6.5.1, also affects master and all other versions.