No way. I figured it out, and of course the answer was the stupidest possible thing, and also one of the last things I thought to consider. The transparency settings were automatically changing to a selection with conflicting values when starting an H scene. That's all it was. I figured this out when I manually changed them, before starting an H scene, had the H scene work, and then checked the boy transparency box, and then got the same crash message that I was getting before.
Of course, I thought of this possible issue hours ago. But the settings appeared normal, with no conflicting checkmarks, before starting an H scene. So I ruled it out. I also still don't know what would cause the transparency settings to change and to crash the game while in conversation.
I previously thought these config settings were global, and applied to every character after you changed them, but it seems like they can sometimes be tied to certain character cards, if you switch player characters a lot. I'm assuming that those settings being tied to at least 3 specific characters was a bug in the first place, because typically changing them applies to everyone. It also seems like manually checking the boxes once stops them from automatically changing when starting H, if that bug had previously occurred. This was such a stupid problem, but directly contradicted something I thought I knew about how the game settings worked, so of course it took a long time to figure out. I feel like an idiot, but I'm just glad I don't have to fully remake any characters.
