What is discoloration that follows the grain of a CD? Options

[FrgNdTd]

In advance I apologize for my lack of correct terminology. I noticed on some of the albums I own, both new and well used various spots of discoloration appear on the information side of the disc. It is incredibly subtle and seems to follow along the CD's grain or rings sometimes veering off slightly to make a larger splotch.

Despite this odd aesthetic appearance the albums play and rip fine. I'm curious if the discoloration is a result of the method used to press the CD or perhaps some sort of warping developed over time.

Thanks.

[FrgNdTd]

I appreciate the response. I think it's possible it could be early stages of that. It's mostly towards the center of the disc. Can rot account for wavy off colored lines circling the CD?

[probedb]

I appreciate the response. I think it's possible it could be early stages of that. It's mostly towards the center of the disc. Can rot account for wavy off colored lines circling the CD?

I don't think what you're describing is rot. I've noticed it before but just decided it's the way the light reflects off either the plastic, bonding or metal.