Please give this a try:
From GarageSale’s Help menu select “Open User Library”. In that window open the “AuctionWebArchives” folder. Sort it by date and delete the corresponding file.
Restart GarageSale afterwards. It should re-download the listing website and show the correct listing this time.
@kristian: Can you explain what archived auctions are and how sometimes they glitch? I am glad I know how to fix this from now on, but am just curious. I have a lot of archived auctions in the “AuctionWebArchives” folder, will they also cause problems?