I'm on the first mission for The Book of Love quest (initiated from Temple of Mara in Riften). After talking to Fastred and her parents in Ivarstead, I’m presented with the option of talking to either Bassianus or Klimmek to continue the quest. I talked to Bassianus, who tells me that they’re going to elope to Riften, but the quest does not update and I’m unable to advance. I checked in Riften to see if I could find them, but no luck there either. The NPCs in the temple also don’t have any dialogue options to advance the quest either.

Has anyone else experienced this?

I thought my quest had broken.. But I went to the field where the girl was working and she and him were talking about eloping. Then he quest updated. I hadn't left the village yet though. Unsure whether this will work for you having gone back to riften. Good luck

I'll check tonight, but I don't think they're there anymore. I'm pretty sure I've gone back to the field and only saw Fastred's parents there.

Turns out they were in the Fellstar Farm house. I ended up having to pick the lock to get in, but once I did, I saw Bassianus and Fastred talking about eloping. After they completed their conversation my quest updated.

Still a little broken if you ask me, but I'm glad it got resolved.

The one glitchy quest I have on my list remaining is the Miscellaneous one where I need to return Arondil's Journals to Vekel the Man. When I talk to him the quest completes, but they books aren't removed from my inventory and I don't get a reward. I ended up reverting to an autosave before I talked to him so hopefully this gets fixed at some point and I can complete it.