Its purple fringing. Most lenses have it at wide apertures where there are sudden light to dark transitions, and the 70-200mm L MK II is no exception.
If you use lr4, you can pretty well remove it, however, as a side effect, it removes the purple from the entire image, so the skin tones were affected. They can be fixed, but I did not want to spend the time.
Before (Top)
After (Bottom)