I bought my fourth set of NT-01s last Fall, and the prior three sets going back to 2007 I never had any issues with; however, all four of the latest NT-01s had tread splice failure after about 12 runs at a CCA autox on the Performance Center track (perhaps a total of 15 minutes of use). They were properly heat cycled and driven prior to the track use.
You DO NOT want to drive tires with tread splices opening up like these have at high speeds especially. Contact Nitto and demand service. When I sent pictures of what happened to these tires (and after so little use), they offered to refund me and have Discount Tire send them back for analysis. I bought them in November, and I think the build week was 32.
2011.5 M3 sedan 6MT, Silverstone, no sunroof
2001 M5 LeMans Blue/Silverstone
2006 330i 6MT Red/black, ZSP, Nav, etc.
2001 Audi S4 6MT; 1996 Volvo 850R wagon