There used to be a bug at this point, but was actually fixed.
- Do you have a savegame for us before you enter the castle for the first time? (and your current one)
upload a save please here; they're found in (...\Documents\My Games\Enderal)
we'll need the -.ess and the -.skse file; pack both to a archive, the forum doesn't accept *.skse. (please no Auto- or Quicksave)
- what other quests were active?
- Do you use any mods?
- How did you leave the castle, through the door or via teleport? (or console)