What does the quest journal say to do? Did you take enough flesh AND bone runes? Did you bank or destroy any keys?
Be sure to submit a bug if you haven't done so already (those facing the issue) as if there is a bug here it sounds obscure, so we'll need your save data to review. If there's a bug here, it shouldn't take long to resolve.
(But also don't assume that there is a bug, it could be something you have missed, and if it turns out not to be a bug you could be waiting for a really long time...)