Sorry, I can't find the issue. I had a crash once or twice when I was making this event, but I've been testing 6 times after update and it seems I can't replicate this problem. Maybe somehow I fixed this bug in my current dev build.
Just to make sure, you do use the new game folder and transfer old saves into it, right? Not replacing the files, but use a new game folder?
Anyways, I've added a save folder in case you can't pass this problem. Meanwhile, I'll be looking out for more reports on this issue after update.