[bug] DND achievements

[darkstalker]

there are some "invisible" achievements that when getting them you constantly get client errors and break some addons. You can get one of these obtaining the champion title achievement in argent tournament

[dardennf]

Can confirm, with one or all of these quests http://www.wowhead.com/?quests&filter=na=The+Valiant%27s+Challenge

We found it was the Achievement 3696 and it doesn't exist on Wowhead.