I'm not aware of ebay themselves ever having a policy of having to rebid after canceling a bid (not really sure how that could be enforced), but this canceling so close to the auction's ending is new news to me. Historically, once you enter that final 12 hour window, sellers do not have the ability to edit the listing (even when there are no bids), and buyers do not have the ability to retract bids.
I will say though that I cannot recall the last time ebay notified me as a seller that a bidder on one of my items has retracted their bid. I might think there simply have not been any retractions in the last couple of years, except that I know of at least one case where I noticed the bid count drop on an auction item without any notification to me as the seller. So while the ramifications for sellers are troubling if this becomes widespread, it would not surprise me if ebay has taken the stance that auction bids are only final once the hammer falls. And even then, if they're not going to do anything to force payment from a high bidder with buyer's remorse, might as well go ahead and let them off the hook if they get cold feet right before the hammer falls, right?
