I know these guys and watched him the whole time. it had a tiny leak right beside a tread block. if it had been molded just a hair different i don't think it would have leaked. when he buffed the old patch out i actually saw some of the moisture from where we dunked it to find the leak ********* exactly in the middle of where the old patch was.
if i did hit something it didn't leave any trace on the tread and the old patch, as far as i could tell didn't have a puncture mark on it. I looked at it pretty good on the stretcher with a very bright light on it. and if i did hit something and it was exactly the center of the old patch i better go check that lottery ticket i bought that day.