Interestingly I had the same issue on a Racetec K2 rear following a trackday in Belgium last week. It was mostly lefthanders, and I have some tearing which points towards suspension issues (which I expected), but otherwise some scratch lines around the tyre's edge just like yours. Nothing obvious at all in the hugger/swingarm area to have caused it, and the tyre performed fine. I'll try to put up a picture.
Hi You have an excuse you where on a track At the moment havnt done that many miles on it yet as I've been out on the R1 But will be keeping an eye on it and keep ye informed
my bike is in getting tuned and sorting the overheating. havnt been on it in 2 weeks so update not available a mate sent me a pic of his tyre Bridgestone s21 there on a bmw XR similar problem.
