I just find it difficult that the Mossad would be this stupid.
Who knows who it was. Israel's Bay of Pigs, the Lavon Affair, was another agency (they say). Sometimes being too good is bad. Our CIA has been over confident they could get away with anything and got burned.
My guess is something was going on, 9/11 caught everyone by surprise, people who weren't supposed to be nabbed, got nabbed and both Israel and the US want this to go away.
A mistake. Better to take the intel and/or PR hit and get the information out.