SGC's criteria:
40 VG 3: 90/10 or better centering, corners more rounded--but not excessive, stronger creasing may exist. Poorer focus, registration, and discoloration, and staining are more noticeable.
30 GOOD 2: Centered 90/10 or better. This card usually exhibits one or more of these characteristics: heavy print spots, heavy crease(s), pinhole(s), color or focus imperfections or discoloration, surface scuffing or tear, rounded and/or fraying corners, ink or pencil marking(s), and lack of all or some original gloss.
All I can figure is that the corner rounding is too excessive for the SGC graders to make it a 40/3. The spider wrinkle is not the problem. I don't really care one way or the other what grade it is, I love this card just the way it is, and I don't want Joe P to call me a flipper/investor, Heaven forfend, but when you see the occasional low end 14CJ Matty with skidmarks and gaping bites taken out of the side but with the same grade it just makes you wonder about this whole grading thing.
Note: Large scans used to show card in detail. I'll scale 'em down if desired.