This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
Yes. It appears to be limited to tropical climates. Two articles from
mid-2001 (no longer on original sites, so archive.org links are provided):
The incident in question was discovered by a researcher from Spain who
visited Belize in Central America. What is believed to be a strain of
Geotrichum entered a CD from the outer edge and destroyed the aluminum
reflective layer as well as some of the polycarbonate.
A person in Australia reported a few years earlier that store-bought pressed
CDs were getting eaten, but gold CD-Rs were doing rather well.