I think I might have been too destructive in the liberation missions in Just Cause, because the rebels (who are on my side) are attacking me now. Saving and loading didn't help. It's basically the same problem the pictured forum post is describing. Dude never got any replies, lmao.
Fortunately I kept multiple saves, and one of my older ones seems fine. I'll go back to doing story missions now, but if the game is so jank that it inevitably gets fucked up at some point, then maybe I'll move on to Just Cause 2 without finishing this one.