Yeah I am not sure what's going on, but since I changed to 60Hz on my monitor (so it caps) and game's VSYNC ON (so the game will never get past 60FPS) - everything went smooth without ANY bugs no matter how many times I played. The moment I changed back to 144Hz and VSYNC OFF (so game can go past 144FPS) - I noticed the bugs coming back right off the start.
The most frustrating part was the ending. You don't get teleported inside the stranger's room, you're still outside talking to no one, the dialog still continues. When you're asked to grab the pen nothing happens, you're softlocked and you cannot do anything besides restarting the whole game once again.
If the actions are based on the animations' last frames (like the fade out) - that might be an issue. The GPU and/or the higher the FPS of the game (monitor >60Hz and VSYNC OFF), the more chances it may jump over just one singular frame of the game, that's all it takes for the game to not register that ending.
My idea would be check the player's camera position (XYZ) at the end to see where does it actually land on - even though it might go inside the room, something has to interfere with it and teleport it right back outside in a split second.
That's my take on it, hopefully it helps you in a way or another and figure what's the actual issue behind it. Wishing you all the best!! ❤️