I was helping a friend decorate her Grotto, but we couldn't get a rug to work (dang crooked floors), so she gave me the rug to use in my Xanmeer. Upon trade, I saw the item added to my inventory on the pop-up and ported out to my Xanmeer. Couldn't find the item in my bags, her bags, my house, her house... it was gone. Asking around in my housing guild, someone said they'd heard of a bug where trading furnishings in houses could cause that furnishing to disappear.
At least it was only the rug that disappeared, but I thought I'd bring this up and see if anyone else has experienced this. Beware!