A licensed jumper switching canopies noticed this wear to the retaining loop, the component of the 3-ring system on the risers that attaches the main canopy to the harness. The damage could have caused the retaining loop to break when the system was experiencing the highest load, such as during deployment or on a sharp turn. If it had broken, it would have released one riser, which would have been catastrophic if it had happened too close to the ground for the jumper to perform emergency procedures.
This was probably not routine wear, since the risers were not very old. It’s most likely that the damage occurred during an event such as the container being packed on an abrasive surface or being dragged across the ground during a rough landing. This highlights the importance of thoroughly checking all components of the parachute system on a routine basis.