Nexus 5 colour shifting artifact

A few weeks ago the pictures coming out of my Nexus 5 started having this weird colour shifting artifact.

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Note how the green is bleeding off to the right. Look a little closer and there's a strange colour shift across the entire image. Also on the left side of the image is a bar of digital artifact of some kind. Strangely enough, it only appears to happen when taking pictures in portrait orientation. It doesn't happen when I take pictures in landscape orientation.

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Even more strangely, it also doesn't happen if I turn the N5 180 degrees (using the phone upside down).

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Not entirely sure what's going on here, and so far my Google-fu has been unhelpful. I'm wondering if one of the tumbles my phone has taken recently might have messed something up.