Welp, my ears weren’t deceiving me. I have camshaft wear again after 10,000miles. This is a fault in the Cummins roller lifter design, which I’m assuming allows a rotational wobble due to a small key on lifter compared to keyway in block. This causes sharp corners of roller to dig into the lobe, which stops the rolling causing more scoring. Furthermore, rollers show blueing which is evidence of heat damage from said scoring.
Three different lobes pictured.
View attachment 66693View attachment 66694View attachment 66695