Hey, i have a problem. I've done every single daedric quest, including Boethiah's Calling, but I can't get the achievement because the miscellaneous quest 'Investigate the Boethiah cultist' remained even after I investigated him and started and finished the quest. I'm more annoyed because I just want the achievement and I don't really want to start a new game. I also know I've done all 15 quests because that's what my stats say. Any help to fix this? I appreciate any effort. Thanks!

maybe this will help you. http://www.uesp.net/wiki/Skyrim:Boethiah%27s_Calling