i also received this problem on my purity route as i mentioned this as well at an earlier post a long while ago, at first i didn't know what to do, the setting was in some restaurant but the background was black, then the next day and everything is black, i didn't know what to do. so i went and tried another route, and i got to the same restaurant event but this time it wasn't black, there was background and everything, then it went to the next day, and i was at the house, in this route i needed to head outside to go to a stadium with the son. this got me thinking, i uploaded that purity route save file and the day after the restaurant event, i started moving around with the arrows as if i were to exit my room, and sure enough, found that the character was in her house as after moving, she commented about that closed door that was right across her room. so i moved to the right till she went downstairs, then by memory, arrowed my way through the door exiting the house, out of the house and out of the gates of the house and the event in where the son takes you out to the stadium started. afterwards, it gets back to normal.
it is tricky getting out of the house when you can't see nothing, so it's better to practice on save file in where the map is normal and practice the movements to get out of the house from your room. once you think you got it down, try it on the purity route save file, to activate the next event.
i would have expected .88 patch to fix this, i guess not.