So when I was doing chain maintenance I notice two "slices" in my rear tire. Neither is very deep but still disconcerting. This tire has about 3K easy miles on it, bought it new last September.

Here are some pics with the end of a zip-tie for depth reference, it doesn't even come close to the first notch on the end of the tie. My question is, does this warrant replacement? Do you think it was something on the road or manufacturing defect?