I tried something for my new playthrough: for some reason, I thought that maybe the issue is caused by overwriting saves; so I'm playing without quicksaving, just regular new save every time I need to, without overwriting. I much farther than I was when I got my issues, lvl5, traveling after fort joy. I got no issue with the central area of fort joy no matter how many times I went back and forth, got no issue with teleporting to the statue in fort joy, no save/load issue either.
Could be coincidential, could be that the bugs are waiting somewhere farther in the game, could be that not overwriting saves is a solution. I'll keep playing like this and I'll come back here to update.
