Actually, I ran into this bug while I was playing demo 5 as well, and when I pressed rollback, for some odd reason the buttons in the top left corner of the screen disappeared, so I just continued to play to the credits. (For context, the bug happened during Soutarou's route, and during the same scene).
I did play the game over again when this new update came out, and I even uninstalled demo 4 before I downloaded it. (I was playing on Android btw).
I originally thought maybe I had done something to the game on accident, but it seems to be a bug instead.