Topps GOlden Giveaway Trade Glitch?

[cmnkb8]

So someone offered to trade me Joe DiMaggio for Stephen Strasburg on the Topps Golden Giveaway site. I went to hit Accept and then Yes to confirm, but then the message: "This action failed because there isn't enough of this card available for this trade" popped up. The trade offer is still there in My Trades even after I refreshed and declined other trades. First time I've had that happen, and I've accepted over 40 trades on the site. I have 3 Strasburgs in my account, so it's not me. Could it be the other person trading DiMaggio no longer has the card and the system failed to cancel the offer, or is this some sort of temp site glitch? Anyone know?