I CTD when I close the barter menu, but only when there is a sizable transaction (as in many items being exchanged). This is reproducible but I can also circumvent it by doing small transactions and not spending to much time idling in the barter menu. I think a couple of people have already reported this? I also recall encountering the same bug in FO3 before it was mysterously fixed in a patch in which this was not even listed as a bug. Anyone else?

try to stash your poker cards and try again, see if that helps.

Yeah, I noticed the same thing, see http://www.gamesas.com/index.php?/topic/1136044-repeatable-crash-with-caravan-merchant/

But like knight_9 says, I started thinking, I didn't have any problems with the guy when I just limited myself to non-card items, so the chance that the cards cause issues is fairly high, despite not being able to use them as of yet on PC, I do pick 'm up whenever I encounter them, including in my tests yesterday.

Actually, I use a mod that fixes the bug where caravan cards were not being added to the deck automatically. This addressed the CTDs I use to experience with merchants that had duplicate cards in their inventories, so this is not the problem.