Parece ser um bug na sua versão, de fato.
Eu tentei com o MySQL 5.5.8 e lá está classificado corretamente:
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.5.8 MySQL Community Server (GPL) Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> select * from test order by title asc; +----+----------------------------+ | id | title | +----+----------------------------+ | 4 | ABCDEFGHIJKLMNOPQRSTUVWXYY | | 3 | ABCDEFGHIJKLMNOPQRSTUVWXYZ | | 1 | record1 | | 2 | record2 | +----+----------------------------+ 4 rows in set (0.00 sec) mysql> select * from test order by title desc; +----+----------------------------+ | id | title | +----+----------------------------+ | 2 | record2 | | 1 | record1 | | 3 | ABCDEFGHIJKLMNOPQRSTUVWXYZ | | 4 | ABCDEFGHIJKLMNOPQRSTUVWXYY | +----+----------------------------+ 4 rows in set (0.00 sec) mysql>
