This is die wear. On the older style of dies with the multiple hub process, the devices are a higher profile. Thus when the die started showing die wear, it started with the outside edge of the devices towards the closest rim direction. Die flow lines form first on the fields. When they are polished off, then the die scratches in the open fields flatten first. But the devices will show what we are seeing on your coin. A walking of the devices towards the rim direction on that side. This is normal die wear. Each time the fields are polished down the same pattern starts again. (Because of the movement of the metal is always in the same direction. As more and more polishing happen, the more of the devices move to the area near the rims:

As the aging continues, the more unlike the devices become.
DDD is seen on the lower price cents of the single squeeze process. How are they different from die wear? Well bother are die wear, but on the single squeeze dies, just the fields show the distortion at first. Later
Ridge Ring distorts the devices. But on the earlier dies, it is the outside edge of the devices that are affected, unlike just the fields are affected on the
DDD.
Multi-hub die wear pattern:

Again note the area affected is the outside edges of the devices moving towards the rim.
On
DDD, the Fields are showing the die wear first:

Note the pattern? The fields are affected versus the devices being affected. Later as the die continues to age, the
Ridge Ring appears:

So both are called die wear. But only refer to the single squeeze dies as
DDD.