This is a CROP of an extreme example of CA with the 20-35mm / f2.8 lens. Shot at 20mm with f2.8 (wide open) at ISO 1600. No post-processing - shot in RAW with in-camera trimming and JPEG conversion. This was the ONLY picture that showed this CA problem. Again, this is a small crop out of a larger picture.
I should have definitely stopped down a little (which I did in other shots).