I have struggled with this issue for a long time and can't seem to:
1. Stop I from happening
Or
2. Find the unprocessed RAW file.
I have it set take both a 5mp and 34mp photo.
Help
The white balance debate has been an issue ever since they started tweaking camera algorithms, and making it better or worse. You could always edit the white balance with Lumia Creative Studio or import into software like DxO OP10 or Photoshop CC on your computer.
In order to shoot in RAW, you must have the '5MP JPG + 34MP DNG' option checked - .dng being the RAW file format used. Unfortunately, you can't have a 34MP RAW and JPG setup. Editing white balance from a RAW file format is much more effective, and so I'd recommend Camera RAW, DxO Optics Pro 10 to do so, or if you don't have the money, I've heard good things about Rawer