Mitchel Broussard at MacRumors:
Apple yesterday began contacting some customers who recently purchased third-generation Apple TVs, informing them that their devices had shipped with an unspecified faulty part and offering an exchange for a brand-new unit shipped from the company.
As Broussard points out, this is a highly irregular way for the company to be dealing with this, leading many to believe (myself included) that this affects a very small number of units.