1987 D penny, here again the plating blisters. There looks to be a cracked rim, and also the plating on the reverse with the silver coming through is that just pmd or a plating error.
Its a Ridge Ring caused by a worn out die, not a crack.
The date and mm have die deterioration. If you're asking about the patch of silver coloring on the Left side of the Lincoln Memorial, its only staining
staining and die deterioration. Thank you. I appreciate it.