Forum:Broken quest

This is something that happened ages ago but I never got round to posting a question on the forums. On my Berserker character there is a mission called "Talk to Tannis" which involves going back to Tannis's cell in the Crimson Fastness and talking to her. Trouble is though that she isn't there because the mission came up after the end of the campaign (I think) and now she is back at her digsite. What's more is that this hasn't happened to any other character, just this one. Have I done something wrong and is there anyway to fix this?