The table cm_co_sequential_identifier_assignments_i1 has a unique constraint based on co_identifier_assignment_id (an integer) and affix (varchar(256)).

In MariaDB, index prefixes can be up to 1000 bytes long for MyISAM, but only 767 bytes for InnoDB. While 256 + 4 < 767, with UTF8 enabled each char gets 3 bytes, not 1, so (256 * 3) + 4 > 767.

Consider changing affix to varchar(250), and checking for other indexes this might affect.