I ordered 2 Michelin pro-race2 tyres from a british mail order company. 1 seems ok. On the other, the grey rubber outside has turned white in places and seems to be showing the threads. This is happening on one side at the fold of the tyre. I have not taken it out of its packaging, so I can not see the extent of the apparent aging/wear. Returning the tyre to England could cut into the savings I had. I do not believe photos would adequately show the situation. Should I keep the tyre and ride it on the back or should I suffer the costs of returning it to England?
I have a pro2 race that has some separation from the rubber tread and the tire casing... it sounds like the same problem you are describing. The problem showed up after about 200 miles... but the structural integrity of the tire didn't appear to be affected. I kept on riding the tire. I have almost 2,000 miles on it now, and it's going to need to be replaced soon due to tread wear. That manufacturing imperfection never caused a problem (of course, YMMV).