More likely a laminate separation- the red line is not dead money vertical, but follows the radius of the laminate, as shown by the Magnaflux dye process. In two of the boiler and pressure vessel shops where I welded to ASTME codes in my working years- the Magnaflux process was used a great deal--first time I have seen such good photos of such a dye penetrant Magnaflux test on shotgun barrels- Bravo--

"The field is the touchstone of the man"..