I didn't have any bugs or anything similar. I got all endings in one go too.
I was recommended this game by a couple of friends and they all got all the endings and didn't have any bugs.
If I have to guess, your SAVE could be corrupted so try maybe starting a new game and see if that fixes the problem for you.
Also you can press ''Ctrl'' on your keyboard or use the skip function in your main menu to skip through the game
and reach the ending you want in a few minutes if you want.
Now this final thing is just a personal request but if my comment helped you please consider checking out and supporting my youtube channel