It may be a good idea to start checking our engines with a bore scope on a regular basis, I know that I am going to scope mine now.
  I have seen signs of chatter before but it was very light where you could see it but it was smooth to the touch, I saw this in one of my very early engines with the 3 piece seals and in the last engine I rebuilt that had 3mm Mazda seals, I am currently using those housings with the 2mm seals that Tracy sells.
  Ken