When adding a new domain with MySQL enabled, I get the following error message:
Creating MySQL login .. .. MySQL database failed! : mysql::execute_sql_logged failed : SQL insert into user (host, user, ssl_type, ssl_cipher, x509_issuer, x509_subject, plugin, authentication_string) values ('localhost', 'EXAMPLE', '', '', '', '', 'mysql_native_password', password('REMOVED')) failed : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('REMOVED'))' at line 1 at /usr/libexec/webmin/web-lib-funcs.pl line 1493.
After digging a bit, it seems that the PASSWORD() function has been deprecated as of MySQL 8.0.11. I am running MySQL 8.0.12.