Basically over time there seems to have been a bit of duplication in a few tables (buddies, moderators, maybe a couple more). Not an easy way to fix these with a SQL command. Probably the easiest would be to do it via something like phpmyadmin.
Really need to clean these up for 8.0. First getting rid of old dups, and second making sure it's not possible to add a dup in the first place.