CASE 1- Puncture
One of the most common issue faced by motorists for their tyre. And for a start, the moment there is a puncture, or a puncture related defect, it is not covered by warranty.
In this particular case, the embedded nail had its tapered top worn off, and it was hard to spot. The driver continued driving not knowing there was an embedded nail. In this particular case also, the air leak was possibly very slow, and it resulted in "seepage" of air and water vapour into the various plies in the tyre. Ultimately, the various layers separated, resulting in bulging of the tyre.
Drivers in such cases usually notice the problem too late, when the car starts vibrating (sometimes violently), or when the tyre concerned starts producing loud "flapping" noise.