[MariaDB 10.3 -> MariaDB 10.6][InnoDB] Duplicate entry '...' for key 'unique_index'

Recently we upgraded mariadb from 10.3 to 10.6 and we are facing a weird problem.
Although there is a unique key on 3 columns (`table_hash`,`table_id`,`meta_key`) there are multiple records with same data.
It didn't happen when we were on mariadb 10.3.

*Table structure:*
```

CREATE TABLE `ordini_meta` (

  `meta_id` int(11) NOT NULL,

  `table_hash` bigint(64) NOT NULL DEFAULT 0,

  `table_id` int(11) NOT NULL DEFAULT 0,

  `meta_key` varchar(50) DEFAULT NULL,

  `meta_value` longtext DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_general_ci;

ALTER TABLE `ordini_meta`

  ADD PRIMARY KEY (`meta_id`),

  ADD UNIQUE KEY `unique_index` (`table_hash`,`table_id`,`meta_key`),

  ADD KEY `table_hash` (`table_hash`),

  ADD KEY `table_id` (`table_id`),

  ADD KEY `meta_key` (`meta_key`);

ALTER TABLE `ordini_meta`

  MODIFY `meta_id` int(11) NOT NULL AUTO_INCREMENT;

```

*Example of duplicates*:
Duplicates

Rows in the table are managed with PHP and the query used is:
```

INSERT INTO ordini_meta (table_hash,table_id,meta_key,meta_value) VALUES (%d,%d,%s,%s) ON DUPLICATE KEY UPDATE meta_id=LAST_INSERT_ID(meta_id), meta_value=%s"

```
*SHOW VARIABLES 10.6(now):*
pastebin

*SHOW VARIABLES 10.3(before upgrade):*
pastebin

DB structure is the same that was in 10.3, unique key was already there before upgrade. In 10.3 there weren't any duplicate rows. We restored the database from a backup(mysqldump) and everyday we need to delete duplicate rows. We also tried to re-create index many times. I suppose I just need to create a bug report

We really don't understand why it happens.
Any help is really appreciated.