Well, I have to go and look but...
I understood that the challenger AKA previous highest bidder before the end of the FA period, or the original player's team, could contest the player and I understood that those two had to explicitly make their intent to challenge the winner in a bid-off; however, I am genuinely confused because I thought the winner at the end of the FA period assumed the rights of the player unless challenged, but I don't see the reason for that individual to state their intent to accept a bid-off from a challenger. Just slightly confused here.