Sounds like the same issue on the Memorial reverses. As the die ages the polishing of the dies and die clashes can affect a die crack issue on the higher devices. Always reminds of of a Peanut Cartoon years ago (1956)

The stress of the strike and the aging of the die along with die cracks makes this happen more often on some designs. Never though of this one before, but it will be added to the list going forward. Thanks for posting this.
CoopHome:
What causes die cracks on certain areas of the design, seen on later die state coins? The weakening and die events of the aging die states. also figure in die cracks, thus the die are still used, and more die cracks can appear.