If you look you'll see that the off-colour parts are at the lower end of the brightness range ( darker ) and their is also evidence of a flare on the right hand side of the image.

The combination of these things probably threw your auto white balance off a bit and the darker pixels, which are more prone to error anyway, got thrown off the most. This has led to your odd looking colours.

How to combat these things :

• Use a hood. Always. I'm guessing you did not based on the flare. A hood would probably have eliminated that.

• Don't expect auto settings to work. If you want to get the result you expect, shoot RAW ( where you choose white balance during raw conversion ) and expect the odd problem in difficult situations.

• If you use a so-called protective filter, remove it and keep it off unless you;re shooting in hostile conditions. These things make flares and other optical issues more likely.

• If you shoot JPEG, choose a white balance setting. Do not rely on auto white balance. One reason to shoot RAW is that in JPEGs you cannot always undo the white balance if its wrong. With RAW you get the maximum scope to adjust white balance. Many cameras allow RAW+JPEG and this is a useful choice if you just want the RAW for occasional use and you can ignore it or delete it if the JPEG turns out OK for your needs.