I have no yet found myself to own any disc with actual disc rot. When it comes to actual manufacturing errors, I have only had discs that experience bronzing.
Disc Rot itself seems fairly uncommon, as it is only widely known to have effected pressed CDs and LaserDiscs from a specific plant in England in the early 90s. Disc Rot has no bearing on how the disc is stored, as it occurs within the sealed layer of the disc.
I would check the top layer for defects. The top layer on most discs also provide a reflective surface. A lot of CD or DVD lasers will have problems if portions of this are removed, even if it is just a single whole or larger patches, even though the data layer itself is still good and free of defect. I have experienced top layer deterioration on various formats such as Marvel vs Capcom on Dreamcast, some Sega CD games, music CDs, etc.
Disc warping is a thing, but I have not seen a slightly warped disc have a problem being read. The worst you would get from an actual warped disc is that it will physically break at some point during the spin, due to it not being balanced.