This has nothing to do with the quest, but god I hate when you pick one dialogue option, but the game is hard coded to have the conversation partner always respond to the last option, most often because it's just a broken up sentence anyway. But here it really was a different option, and furina just responded to something I did not pick at all. It's relatively minor but really makes you realize that the only reason these dialogue options even exist at all is to prevent people from autoplaying the story while they do something else.