a lot of their tires run a dual-compound rubber, with a softer rubber on the inner treads. They do this knowing that as the tire ages, the rubber hardens. This way, as the tire wears and the rubber hardens, a new softer layer is revealed to prolong traction. It looks to me like that's about the right tread height. It's a feature - I happen to like it.
I have no idea if this is attributable to a tire problem, a driving incident, a traction moment, rolling over gravel during a stop... and if it's only in that one spot it's more likely to be a road hazard than a tire problem. If it's happening around the tire, that leans towards a tire problem rather than a road hazard IMO.
I've owned many sets of bridgestone tires advertising the feature. However, I've never once seen them shed like that. If you bought those tires, I think I'd take it in and ask for them to look at it as a safety issue, specifically ask about tread separation, and see what they say. If they say it's not an issue, I would ask for them to write on the ticket that the tread separation is normal and ask them to staple that picture to the receipt. If they are willing to sign their name to that, with the picture, they'll have to think about that a bit.
-m
