Having a major problem with the aforementioned quest. I return to Riverwood after finding the horn not in the expected place, enter the inn, and Delphine is nowhere to be seen. After using placeatme to get her back, I pick the "Attic Room" topic which grants me the room but Delphine never comes to me like she should, and speaking with her again only gives the single room rental topic.
Research found two possible culprits. One blamed Guard Dialogue Overhaul, but disabling that and loading an earlier save made no difference. Others seemed to think it was a strange bug from having started the "Innocence Lost" quest first (which I have). I have an earlier save from before that but do what to have to go through the whole horn dungeon again unless I have to.
I tried numerous combinations of console commands to advance the quest and move cleanly to the next but nothing worked. Does anyone know how to work around this issue with the console (research suggests it to be reasonably frequent) or maybe know of another mod issue as a possible cause?
Thanks.