i found error that trade post can be using to copy items.
i insert few items in to trade post. for example few offers with same item. in my test 5 x vostaskus bar.
then i select 2 different same offers and buy them.
Trade post will lose 1 item, and i will get 2 items to inventory.
from my inventory money will be gone, but trade post will not get anything.

and end of transaction.
1 position from trade post vanish. trade post gets nothing, and i get 2 vostaskus

And same with 3 same items.

Hey,
thanks for this detailed report.
I've already fixed this in December, based on this report. But it seems like the updated version was never uploaded to the feudaltools server .

The fixed trading post version should be live now. Please verify the version in the Trading UI bottom. It should say 1.5.3 now.

I tried to reproduce this issue in 1.5.3. No errors there.