Can not add a foreign key (with a weird reason presented) when there is a UNIQUE multiple column index on the column with a long VARCHAR(N) as a suffix

MariaDB [test]> create table A 

    -> (

    -> IDA int(19) primary key,

    -> someTextA varchar(1000)

    -> ) engine = innodb;

Query OK, 0 rows affected (0.095 sec)

MariaDB [test]> create table B ( IDB int primary key, someTextB varchar(1000),  someInt1B int, someInt2B int, fk_IDA int(19)

) engine = innodb default charset utf8mb4;

Query OK, 0 rows affected (0.085 sec)

MariaDB [test]> alter table B add constraint unique_B unique key (fk_IDA, someTextB);

Query OK, 0 rows affected (0.196 sec)              

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> show create table B\G

*************************** 1. row ***************************

       Table: B

Create Table: CREATE TABLE `B` (

  `IDB` int(11) NOT NULL,

  `someTextB` varchar(1000) DEFAULT NULL,

  `someInt1B` int(11) DEFAULT NULL,

  `someInt2B` int(11) DEFAULT NULL,

  `fk_IDA` int(19) DEFAULT NULL,

  PRIMARY KEY (`IDB`),

  UNIQUE KEY `unique_B` (`fk_IDA`,`someTextB`) USING HASH

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci

1 row in set (0.003 sec)

MariaDB [test]> alter table B add constraint B_fk_ida foreign key (fk_IDA) references A (IDA);

ERROR 1005 (HY000): Can't create table `test`.`b` (errno: 150 "Foreign key constraint is incorrectly formed")

MariaDB [test]> show engine innodb status\G

*************************** 1. row ***************************

  Type: InnoDB

  Name: 

Status: 

=====================================

2024-03-12 15:12:21 0x700001255000 INNODB MONITOR OUTPUT

=====================================

Per second averages calculated from the last 34 seconds

-----------------

BACKGROUND THREAD

-----------------

srv_master_thread loops: 0 srv_active, 0 srv_shutdown, 388039 srv_idle

srv_master_thread log flush and writes: 388039

----------

SEMAPHORES

----------

------------------------

LATEST FOREIGN KEY ERROR

------------------------

2024-03-12 15:12:11 0x700001255000 Error in foreign key constraint of table `test`.`b`:

Alter  table `test`.`b` with foreign key `B_fk_ida` constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns.------------

TRANSACTIONS

------------

Trx id counter 906470

Purge done for trx's n:o < 906468 undo n:o < 0 state: running but idle

History list length 0

...

MariaDB [test]> show create table A\G

*************************** 1. row ***************************

       Table: A

Create Table: CREATE TABLE `A` (

  `IDA` int(19) NOT NULL,

  `someTextA` varchar(1000) DEFAULT NULL,

  PRIMARY KEY (`IDA`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci

1 row in set (0.000 sec)

MariaDB [test]> alter table B drop key `unique_B`;

Query OK, 0 rows affected (0.182 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> alter table B add constraint B_fk_ida foreign key (fk_IDA) references A (IDA);

Query OK, 0 rows affected (0.203 sec)              

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> show create table B\G

*************************** 1. row ***************************

       Table: B

Create Table: CREATE TABLE `B` (

  `IDB` int(11) NOT NULL,

  `someTextB` varchar(1000) DEFAULT NULL,

  `someInt1B` int(11) DEFAULT NULL,

  `someInt2B` int(11) DEFAULT NULL,

  `fk_IDA` int(19) DEFAULT NULL,

  PRIMARY KEY (`IDB`),

  KEY `B_fk_ida` (`fk_IDA`),

  CONSTRAINT `B_fk_ida` FOREIGN KEY (`fk_IDA`) REFERENCES `A` (`IDA`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci

1 row in set (0.003 sec)

MariaDB [test]> drop table B;

Query OK, 0 rows affected (0.102 sec)

MariaDB [test]> create table B ( IDB int primary key, someTextB varchar(1000),  someInt1B int, someInt2B int, fk_IDA int(19)

) engine = innodb default charset utf8;

Query OK, 0 rows affected (0.073 sec)

MariaDB [test]> alter table B add constraint unique_B unique key (fk_IDA, someTextB);

Query OK, 0 rows affected (0.177 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> alter table B add constraint B_fk_ida foreign key (fk_IDA) references A (IDA);

Query OK, 0 rows affected (0.180 sec)              

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> show create table B\G

*************************** 1. row ***************************

       Table: B

Create Table: CREATE TABLE `B` (

  `IDB` int(11) NOT NULL,

  `someTextB` varchar(1000) DEFAULT NULL,

  `someInt1B` int(11) DEFAULT NULL,

  `someInt2B` int(11) DEFAULT NULL,

  `fk_IDA` int(19) DEFAULT NULL,

  PRIMARY KEY (`IDB`),

  UNIQUE KEY `unique_B` (`fk_IDA`,`someTextB`),

  CONSTRAINT `B_fk_ida` FOREIGN KEY (`fk_IDA`) REFERENCES `A` (`IDA`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_general_ci

1 row in set (0.003 sec)