White iPhone 3GS discoloration due to cases, not heat?


Heat has been blamed for marring white iPhone 3GS backs by customers. The complaint is if the battery gets hot enough, it discolors the phone, creating a red-ish discoloration as depicted in the picture from freshiphone.com.

What's curious about this issue, is by the pictures I've experienced the same thing on my original iPhone. Except it was from a case, not heat. I could clean the red coloring off with a cleaner and cloth, at least on the original iPhone's metal back. I've also seen other white 3G owners who have similar discoloration blamed on cases. Likely, black iPhone users are experiencing the same thing, but just don't notice.

CNET relays an English translation from FrechiPhone who was told by Apple techs the issue is in fact not heat related, but case related. The case in question for me was the Incase Protective Cover, a black silicone/rubber case. Perhaps there's a rhyme or reason to this discoloration and specific cases or type of cases. Anyone else notice this?