One guy I remembers had dozens of retracted bids, claiming error. He simply wanted to expose the highest bid.
I've seen bidder profiles on eBay
that retract literally hundreds of bids monthly. Many have placed well more than 50% of their bids with the same seller. My impression is that many of these accounts are shill accounts, seeking to see the high bid before placing a shill bid.
There are a few dealers I know who run "auctions" but shill bid.
Some dealers have gotten smarter and place shill bids in the last seconds of an auction. Removes the visible signs of shill bidding by removing most of the shill bids. Agree that many of these lots will reappear. I suspect this is a strategy sometimes also used in conjunction with private auctions.