I am unable to find an official online source for this but can confirm it is fact due to having all 4 injectors replaced on my A3.
The recall is due to faulty injectors on Diesel VAG engines built between 06 and 08 which can fail spontaneously and cause the engine to cut out (which won’t be good at motorway speeds!)
Its advised that anyone with a Audi , VW , Seat or Skoda 2.0 Diesel to contact their local dealership with the VIN number and they can advise if you are affected. Some 1.9 engines are also affected.
The process takes about 2 hours to check if they need replacing and a further 2 hours to replace.