The story has become unplayable.

After defeating the boss at Sale's Megaliths during the intermission, I spoke to Una once and heard the sound effect and saw the text indicating one quest had progressed. However, when I returned to the scorched farm and tried to proceed to Blackwood, the quest list on the right side of the screen instructed me to go to Sale's Megaliths. When I headed to Sale's Megaliths, the quest prompt changed again, telling me to talk to Una once more. However, the conversation option for Una's quest was grayed out, and I couldn't progress the story at all.