Yes. A bidder can retract a bid during the time the auction is open.
While there are a limited number of reasons given they all come down to the same thing.
The bidder has changed their mind, they don't want the item any more, and if they won they would not pay for it.
Sellers can also cancel bids during the auction period. And again, while there are reasons given, they come down to the seller does not want to deal with that bidder, and no one can pay him to deal with the bidder.
You can add the bidder to you Blocked Bidder List if you like. But mostly be glad you don't have to deal with an Unpaid Item Dispute tying up your listings for five days.
