Inexplicable precheck errors when attempting to upgrade Aurora MySql 2.11.2/5.7 to 3.06.0/8.0.34

We have previously successfully updated our development and staging databases to Aurora MySql 3.05.1/8.0.32. But when trying to do a dry run of upgrading our production database, the latest version of the upgrade precheck raises "MySQL 8.0 syntax check for routine-like objects" errors for stored procedures that previously passed without problems, and runs fine in MySql 8. For some of the errors we can simply not figure out what is causing these precheck errors. An example of a stored procedure that gets rejected:

CREATE DEFINER=xxxxxxx@% PROCEDURE BO_GetCurrencyRoles() LANGUAGE SQL DETERMINISTIC READS SQL DATA SQL SECURITY DEFINER COMMENT '' BEGIN SELECT i.name AS ccy_name, cr.name AS ccy_role FROM currency_role_mapping cm INNER JOIN instrument i ON cm.currency_id = i.id INNER JOIN currency_role cr ON cm.currency_role_id = cr.id; END

For this stored procedure we get this precheck error: "level": "Error", "dbObject": "unify.BO_GetCurrencyRoles", "description": "at line 4,17: unexpected token 'AS'"

As far as we can see, we have quoted all names that could conflict with reserved names. If somebody could point out what we are overlooking, it will be greatly appreciated.