Not necessarily shilling.
In fact, shill bidders don't want to win. They want you to win at the highest possible price they can push you to.
The usual sign of shill bidding is a nibble bidder who finally uncovers your maximum bid, then retracts their bids.
Leaving you paying more than you needed to -- though not more than you were willing to pay.
I'd guess the low FB winner reneged on their bid within minutes of winning. The seller is really really annoyed.
Alternatively, the seller has more than one of the item but has chosen to make them appear more attractive by using auction format and is selling them one at a time.
