Merchant disposition is tied to whom you use to talk to them. And your cha influences prices WAY more then you can by bribing them. But it stacks. When the disposition changed you probably accidentily used someone elae to talk to them.
I'm aware of this. (Point #3.) I used Wyll to start the conversation both times. Maybe a bug?
It was the zhent trader in the goblin camp. But I didn't do anything to advance the plot -- it was just reset after a long rest.
Reall, I don't think it really "makes sense". I can switch characters in the trade UI, and the prices don't reset.
Merchant disposition is tied to whom you use to talk to them. And your cha influences prices WAY more then you can by bribing them. But it stacks. When the disposition changed you probably accidentily used someone elae to talk to them.
#2 is true in some cases. It already happens. But its a potential spoiler. Lets just say that what you suggest happens in a different way and isent represented in the prices.
If the "some cases" are before Act 3, can you spoiler-tag them for me, please? I know sometimes merchants give you quest rewards, but that's hardly the same.