Merchants not returning proper amount

[Traul]

Relogging doesn't change anything for me. And I really don't think it's a rounding issue, it always gives me the same amount of silver in copper even if it's off by 1. Here's some screenshots to illustrate:


Here I'm about to sell a diamond for the listed price, notice it will give me 2 silver, but 0 copper:



And now I sell 1 of them and look, I get the 2 copper instead of none:



Now I'll sell all 19 of them (I deleted all my money first) and again, I'm given same amount of copper as silver when I should be getting 0 copper:





(split post due to 4 image limit)

[Traul]

This only happens when selling though, buying still works perfectly fine. Here I'll buy the whip pattern and it will remove 5 copper from me just like it says it should:




Now I'll sell the whip pattern back. Since I won't be getting any silver back for it, we can predict I won't be getting any copper either (even though I should get 5), and sure enough...





The server is 32bit, and I've gone and logged onto other servers and sold items just fine so I don't think it's a client issue. I have the price mod turned off and buycostmod and sellcostmod both set to 1.00 for testing purposes. This really has me stumped.