Last time I played on version 2.1d I had a rather funny bug where after the auctioneer sold everything he proceeded to sell nothing for around 15000k! I think this is intended as a catch case in case the aution house has the above mentioned bug which I have seen in the past where somehow the auctioneer has 2 items in his inventory so he actually sells them out of sequence, this then catches any leftover items.
I also couldn't remember the command to walk away from the auction house last time so just had to wait through the whole thing, lucky I remembered how to bid. Maybe the help text should be displayed more easily? Like when you enter the auction house area.
I think the doubling up bug sometimes occurs when you leave the AH before or as an auction is ending and for some reason it doesn't destroy the item.