I'm having the exact same problem and posted about it about 20 minutes before you.
I think we'll have to wait for the next patch. The only way I have managed to "fix" it is to scrub back over my saves all the way to before I did any other quests and Orin was still alive.
It seems they expect you to do this quest before going anywhere near the lower city.
I raised a bug report about it, maybe do the same.
