Linear plating bubble. Not the area by GOD. The bubble was pushed in that direction or vise versa. If it were a
Cud the edge of the die would not be present in that area:

The
Cud would be taller than the rim and the reverse would show a weaker area.
If it were a die dent on the outside edge, the coins rim would show, but not be taller than the rim:

Note how it looks like
Cud, but the rim is not taller in that area.
But it is just a gas bubble:

Showing all three scenarios.