Most acquisitions will set aside 10-20% or more of funds into escrow to cover litigation and tax issues that occur, this isn't released for ~4 years after close

Most acquisitions will set aside 10-20% or more of funds into escrow to cover litigation and tax issues that occur, this isn't released for ~4 years after close (stat of limitations on tax returns). So chances are that FB is not paying much if any of the settlement amount and they don't have a big incentive to fight other than not setting a precedent of being easy to sue and win.