Small update: I reloaded a manual save I had right before the Iron Throne. I've been save scumming to check when I get the crash, and I can travel between the two regions so far. Haven't re fought Gortash and Ansur yet, but at this point I'm pretty convinced it was the Steel Watch Factory that broke it for me, because I killed a lot of Watchers before they could detonate previously, and purposefully let them explode on this run to try to avoid the bug. P.S Larian really needs to work on the A.I for The Gondians, because if I didn't have survival instinct on my main character, and a couple Dimension door scrolls left, all of the Gondians would have died, because they kept running right into the Steel Watch explosion radius for literally no reason.
In the testing I've done, I found the Steel Watchers were the main culprit for the 33% crash. I know others in the forum have reported some other enemies causing the issue, but I genuinely think it's the Steel Watchers self destruct that is causing the bulk of the problems.
Finally got back to where I was previously, and my run has been salvaged. Hopefully by patch 4 Larian will have finally fixed this issue, because it is way too easy to run into this game ending bug, and threes no way to even realize it is game ending until it is way too late. If I didn't think to make a manual save prior to the Steelwatch Factory that would have been it.
