Table cannot be loaded after instant ADD/DROP COLUMN

--source include/have_innodb.inc

create table t(a char(5) character set utf8 primary key) engine=innodb;

alter table t add b int first;

--let $shutdown_timeout=0;

--source include/restart_mysqld.inc

check table t;

drop table t;

check table t;

Table	Op	Msg_type	Msg_text

test.t	check	Error	Table 'test.t' doesn't exist in engine

test.t	check	status	Operation failed

drop table t;

Warnings:

Warning	1932	Table 'test.t' doesn't exist in engine

innodb.ia 'innodb'                       [ fail ]  Found warnings/errors in server log file!

        Test ended at 2019-11-19 21:00:04

line

2019-11-19 21:00:04 0 [ERROR] InnoDB: Table `test`.`t` contains unrecognizable instant ALTER metadata

2019-11-19 21:00:04 3 [ERROR] InnoDB: Table `test`.`t` contains unrecognizable instant ALTER metadata

2019-11-19 21:00:04 3 [ERROR] InnoDB: Table `test`.`t` contains unrecognizable instant ALTER metadata

2019-11-19 21:00:04 3 [ERROR] InnoDB: Table `test`.`t` does not exist in the InnoDB internal data dictionary though MariaDB is trying to drop it. Have you copied the .frm file of the table to the MariaDB database directory from another database? Please refer to https://mariadb.com/kb/en/innodb-troubleshooting/ for how to resolve the issue.

		if (!trx_id_offset) {

			/* The PRIMARY KEY contains variable-length columns.

			For the metadata record, variable-length columns are

			always written with zero length. The DB_TRX_ID will

			start right after any fixed-length columns. */

			for (uint i = index->n_uniq; i--; ) {

				trx_id_offset += index->fields[i].fixed_len;

			}

		}