This is the prop on my buddies new boat. We have no idea on the wear marks.
Initially he noticed it on two blades after a day on the water. After a second trip and a few days boating it looked like this. Didn't bury it in the sand or anything. Nothing wrapped around the prop. Remember, this occurred over two trips and the boat was trailered between trips.
This prop is a bit different as the blades are cupped a bit
Yes that is cavitation burn marks .. Here is one site.
https://www.tacomapropeller.com/what-is-propeller-cavitation-causes-prevention-repair/
What is the RPM wide open and what is the max recommended RPM? I'd guss the cavitation is caused by under proping.