Board Thread:Skyrim/@comment-112.209.180.136-20150130090125/@comment-86.147.72.112-20150130113848

Deceiving the Herd is a radient quest so it can have a few diffrent location's and target's the mod author must have added the castle and npc to the list (either on purpose or by accident). Being a radient quest if you have a save before asking for the quest you can load it and ask again you should get a diffent location. At worst you could progress the quest with console commands.