My wife's '05 Prius had a nail in front tire and was half flat so we went to tire store. They, for some reason, took the tire off the rim to plug it after removing the nail. Manager showed me inside the tire, a slight break or split in the inner surface running across the tread (tire width). Is there any known recall or problem in this area that anyone knows of? BTW, he said keep an eye on it and didn't try to panic us into buying a new tire. Afterward I thought, keep an eye on it? It's inside the tire! Should this be covered under warranty? Car has about 12k miles. Maybe at the 15k service I'll ask the dealer about it. Thanks for any input.