Stains in Stainless Steel in iPhone 11 Pro and now in iPhone 12 Pro
Last year, I started to see some staining on the lower right side of my iPhone 11 Pro, which I used with the brown leather case. The stain looked a mix between oxidation, or the rainbow you get after heating aluminum.
I thought it might be related to the leather case, so for the iPhone 12 Pro I bought the clear case. After roughly a month, I started to see the same stain, in the same spot, now in the iPhone 12 Pro. Its located more or less where I rest my hand when I use it right handed. Rest of the rim is perfect on both phones. I do not handle any chemical products whatsoever, and didn't have this issue with iPhone X or iPhone Xs Max. Since iPhone 11 Pro, due to the nice matte back, I try to not use any cases at all.
Genius Bar and phone support said that, due to the issue being cosmetic, and performance is not hindered, no replacement could be done.
Any ideas what could be causing this? Something I could avoid when I get my next phone?
iPhone 12 Pro:
iPhone 11 Pro:
iPhone 11 Pro