1965 Topps Bob Schmidt #20. Unlike most Topps cards with these cut/splice/whatever lines, this one has it on front and back.

1948 Leaf #78 Clarence Self, with sheet marks in the top left is recurring.

1964 Topps #170 Don Rodgers. The blue dot in bottom border on off center cards is recurring.

Exhibits Charley Conerly comes with or without the big slash between his helmet and his hand. Both are common

Somewhere around 50% of 1956 Topps #96 Buddy Young cards have a yellow bottom right corner, like this one.

I also found and bought this copy, with yellow splotching on the bottom left. Not sure if a recurring defect to note or just a random one off. Pretty much any old Topps card can be found with yellow-ink splotching if one looks at enough copies.

Young was only 5'4 and is one of the shortest pro football players. He set some track records before his NFL career, and was a college ball star even as a Freshman. He was the first Colt to have his number retired. With the small set sizes in the 50's, most 'common cards' were actually really good players.

Here is one of mine from the same year. AKA Hunter

1962 Topps Missing Yellow ink?
 

I've seen a few of these 'Blue Box/White Letters' Ernie Davis RCs. A couple are on eBay right now. Looks like a print defect - missing yellow ink? I tried looking for other Green Box/Yellow letter players but couldn't find any examples.

Looks like extended sunlight exposure to me.

That was my first thought. I have seen probably 4-5 of these. There is a PSA 8 on eBay right now. Just odd to see that many with the same 'exposure' or same level of damage. I'll hope to find another player someday....

1962t
 

Looking at COMC - found these blue/green examples. Partials only, however.
One is a 50/50 that looks like damage (sun or water?). The other is just the upper right corner of the green box. Weird?