(This will NOT affect people who have not touched the buttons underground, completed them, or started a new game)
If you had some buttons ON and left the underground and continued with the game then saved and reloaded game then there is a chance the buttons will no longer open the door regardless if you get the order correct when you come back to the area to try and solve it again.
We have a solution
1: Once you load in and if the broken buttons are broken, save game underground and re-load your game. That should reset the puzzle and you'll be able to continue.
Shoutout to https://www.twitch.tv/annedromeda844 for finding this issue!
Minor fix: Some visibility issues.
We're sorry for the inconvenience.