PSA doesn't explain the reasons behind the reject aother than what is listed on their website.
N-5 Altered Stock - This term is used when the paper stock is altered in one or more of the following ways: Stretching and trimming, recoloring and restoring, trimming and recoloring, restoring an trimming, crease or wrinkle is pressed out, or gloss is enhanced.
A black light would be helpful to verify the color & gloss, and to see if it had been cleaned. The card does look legit. PSA may have rejected it because of the scuffing on the inside black framing. Or maybe, they thought that the crease had be pressed out. But it is anyone's guess. I would send it to SGC to see what they say.
I received back 3 boxes from PSA last week. 2 boxes had the wrong labels on every single card. And YES, they want me to pay for them all 47 to be re-graded.
This card has obvious recoloring on the shoulder. I just wanted an AUTH tag put on it, but I got back a Lalonde 1 label. I didn't even submit a Lalonde. The rest of the mis-labels atleast matched another card I submitted.