Not sure if this is a bug or intended, but the Chapter 4 story doesn't seem to have any progression, the only story thing just repeats the end of Chapter 3 where the elf priestess asks to join the harem. I'm asking to confirm because I had a very similar issue when transitioning from Chapter 3 to Chapter 3 where the story didn't actually update until I reset the cache and reloaded. I've done the same thing for Chapter 4, but I'm not entirely convinced since during the huge lag spike at the beginning of Chapter 4 the story just replayed the 3 scenes in chapter 3 (going to the basement, purifying the demons, aftermath/final scene).