First is option for Lev to fly to Elemental Forge greyed out. Nothing you can do to avoid this one. Was originally thought it had something to do with having the pre-access version as this is where the game stopped, and a glitch when upgrading to the full version. I never had pre-access & avoided it when I had my first playthrough, but struck it on my second, & that was the end of the game. So it seems completely random, which is incredible

Second is to avoid going into a dungeon called Tomb of a Thousand Terrors before you get the quest to do so