I heard that at the HAI this year Agusta in the product improvement brief said that they are replacing the screws that hold the probe together and that production alignement will take from S/N 500. And that a evaluation of possible foam modification to allow better water drainage.
Another theory for probe failure is when refueling, fuel is hitting the probe and causing damage.
One aircraft I have we changed 5 #2 probes all with S/N lower than 500. I have one arriving greater than S/N 500 we will see how long that one last on this airframe.