Do you guys with the spots live in humid climates?
I am curious about that, too. Here is a post from last year by Alex Millians, who is a replication insider. I wonder whether there will turn out to be any relationship between the issue he is describing and the appearance of these spots.
GE made a big stink early on with the BDA that because of the non-bonded nature of BD-ROM, PCB would be too suspectible to adverse moisture and uneven warpage for use in high volume BD-ROM replication, thus replicators should use GE's Noryl PPO/polystyrene alloy in lieu of PCB, etc., but no one really listened. Meh.
I agree that the issue might have to do with the coating rather than the climate. Although I do live in a relatively humid climate, none of my other BDs, CDs or DVDs have ever rotted like this. In addition, these spots are not developed on the surface of the disk (thus cannot be rubbed off); I think the spotts actually reside between the clear coat and the disk surface.