If searching by score in a descending way, for example,
https://www.phpbb.com/ideas/list.php?status=0&sort=score&sd=d
It gives an SQL error. Here's a quote of it:

SQL ERROR [ mysqli ]

BIGINT UNSIGNED value is out of range in '(`phpbb`.`community_ideas_ideas`.`idea_votes_up` - `phpbb`.`community_ideas_ideas`.`idea_votes_down`)' [1690]

An SQL error occurred while fetching this page. Please contact the Board Administrator if this problem persists.