i get a similar thing! i was playing the Bitter story on browser, and i got an error trying to achieve ending three, which was the only one i had left... it glitches at the choice where you "return home" from Inori's. So i downloaded the windows version to try to fix it.
Update: sorted! it seems the last part to ending 5 where you return home, isn't wholly translated and it appears in japanese. maybe that's why the browser bugged?
All this aside, i am really liking this game and looking forward to getting all the endings! The characters are super charming, and i like where the stories go a lot.