Wallpaper Periodically Blurring

Ive had my Nexus 6 about a year and the weirdest thing is happening in the last week or so. I set my wallpaper image and everything is fine. But then, later, and I don't know what triggers it, the wallpaper will blur. I can set the image again,no problem, but after a while it happens again. Nothing else on the screen blurs. Just the wallpaper. Anyone else ever have this problem? How can I fix this? Love this phone. Thanks.