Hi! I recently discovered that on the right side, basically above the SIM card slot, I have a very light yellow ring. I tried to capture it in a photo, hope you can see it. I bought this phone in October 2012. I don't know if this issue has been there all along, because it's quite hard to see or if it is a recent thing. I discovered it last week and it's been bothering me ever since. I have read that yellow spots and tint is a quite common issue in 4S. Has anyone had a similar problem and does this defect go under warranty? Thank you.