are you 100% sure nothing ios in the way of the lens?
like a leaf maybe fell, or s stick and then,. was out of way when you go check it?
it happens
normally when I get them shade color like pictures, its normally in the transition of day time to dark pic';s, low sunlight , extra cloudy days
I have had that happen on a few dozen camera's from 35 mm film one's to digital one's, from CHEAP cam's to HIGH end one's
some times it just happens is MY best answer, its a lighting issue IMO , when the conditions and stars align they get some pink or purple to them?
NOW If your getting a HIGH percentage of pic's like that, my guess is something is wrong with camera, maybe camera was drooped a few too many times, rode some place with too many vibrations or??
doesn't have to have happened while you own it, could have happened any time from it left factory y to you bought it!
electronic's don;t like being drooped much all the more so IMO with camera's
I have a High end camera, worked great for 5 yrs, then one day, it fell off bottom step(a whole 10 inches) never worked right since>
out of warranty, and just sucks, was a great camera!