Both previous replies are exactly right. The retracted bid does not reflect poorly on you despite that it may be disappointing. All it means is that the user is a bit of a flake but, ultimately, it’s better for a bid to be retracted than wasting your time with an Unpaid Item action or Cancel Order request when it’s done.
You may choose to block the buyer or not. The retracted bid can be taken as either a sign of a buyer who is unsure of their intentions, or one who is at least clever enough to know how to fix their own error if they decided not to Honour their bid. It remains to be seen. Maybe they’ll be back at auction close, seconds before. Perhaps they bid a high bid and then regret it because another seller recently shill-bidded them to that maximum. I suppose you could send them a message to ask about their concern leading to a retraction, it may be illuminating or it may simply be ignored. Like maybe they simply discovered they won a similar item elsewhere and don’t need two.
Regardless, it’s not a sin to revise a listing while it’s live. That’s the reason eBay allows sellers to do it. Although, yes, once there are bids on an Auction or Best Offer placed on an item that’s Fixed Price, the fields of information that eBay will allow you to edit are limited.