It does have a misplaced mintmark from what I researched . I couldn't find anything to do with the date, I know this 1959-D is a good date error, already had potter look at it .. Was a great piece to talk about, I had to inform Mr. potter who hates wexler RPM #3 that this is what left of it, which proves Mr. potter not agreeing with this RPM as being one . Each to his own I guess . Heres the link to wexler site http://doubleddie.com/1015120.html
That definitely looks more like a lamination issue, the part that you circled looks like it continues down below in a line.