I was shooting a subject that featured a lot of sunlight shining across a surface. In some of the photos, the sunlight appears to have a purple tinge to it. In others, the colours are more natural.
I'm pretty sure it isn't chromatic aberration because this isn't around the edges of the highlight area, it's the whole area. It looks like a sensor saturation issue to me.
EDIT: To clarify, I am using the same manual white balance settings for both.
EDIT: Sorry, I had put the wrong aperture and ISO for the second photo. I have corrected it now.
EDIT: I took a few photos with the camera settings as the first photo and they all had purple highlights. I also took a few at f/22 1/60s ISO800 and none of them had purple highlights. I'm guessing the difference is due to either the smaller aperture or the higher ISO.