I'm not sure if this is a bug or not but when I enter the cave I immediately fail the quest without having it prior on my quest list. This is my first time entering the cave and think Komachi is not even there.
If you wait too long even for the first time you visit she starves. I think it was set to 7 days without food before she starves, so if you found her after that time you have to wait for your next playtrough.
With this day length, you'll be tired of feeding her all the time... but, it's up to you ) The first time I played with a 4 minutes day. And eventually I just left her to her fate, because her feeding took like half of my playing time...
