Hey A-wq! No, the achievement does not require bad endings. Can you save your game to disk and send it to me on adam.ryncraft@gmail.com? That way I can take a look under the hood and see what's going on. Apologies for the issue!
So i uh deleted the save files with the delete all button a few hour ago since i plan on running hard without new game+ and didn't think the save files are needed and the most recent "download to disk" save that i did was before the update.
Can I random save a run and send to you or do i need to get to a certain point then do that?
I'm not sure how the save system work so i don't know what i suppose to do.