In my case, it is because of Sazza. She was in the room with Minthara and got knocked out as well and her quest was never closed. I reloaded the save right before I knocked Minthara and speedrun it to Moonrise 3 times: Without taking Sazza's quest at all, knocking her out by Minthara and killing her by Minthara and the only case when Minthara is broken is when Sazza is knocked and left there. Unfortunately, I can't return and kill her from Act 2, because she despawns (the only one that does that, other gobos I knocked are still there) and I had like 30 hours of playtime from there. This sucks, I'll try to close that quest somehow, but I can't find Sazza anywhere and her marker is gone as well.
