My guess is print defects and centering. The car is pack fresh, subbed with 15 other cards from a box I opened last year (and inspected all of them carefully). The highest I got was an 8.
Either I am bad at grading, or PSA has clamped down on what is considered "Mint"
Probably both. Some of the other cards had a small surface bubble, but most of them are a mystery.
