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).