iPhone 5c - Camera Has Pink Tint In Centre

Hi,

I have a brand new iPhone 5c and so far it's great. But, I've noticed that photos taken of plain solid colours have a pink tint in their centre. Obviously you wouldn't see it in a photo of an outdoor scene in daylight, but indoors it's quite noticeable (see example below).

Is this normal? Will Apple swap my iPhone 5c for another brand new one? I intend to keep this phone for a couple of years, so I don't want all my photos to have this problem.