The Utility mariadb_upgrade does NOT upgrade but prints message:
This installation of MariaDB is already upgraded to 10.6.7-MariaDB.
There is no need to run mysql_upgrade again for 10.6.9-MariaDB.
You can use --force if you still want to run mysql_upgrade
This by itself is not a real problem and can be solved by --force. But we have cases were it is NOT true!!!
10.4.13 still works OK 10.5.17 ff does NOT so it must be introduced in 10.5
See also next bug.