I know it's been a while, but I had the same issue and I have found some explanation to this thing [on this link][1].

The term used in photography is "Purple fringing" and the reason why I "dug" more and tried to understand the issue is that I don't think is a sensor issue (in my case and probably in your case also) because I experienced something like that with a brand new camera and lens - Canon 80D and 50mm f/1.8 lens. 

You can see also my photo attached.

[![Purple Fringing][2]][2]

I hope it helps, even though it's been a while.


  [1]: https://en.wikipedia.org/wiki/Purple_fringing
  [2]: https://i.sstatic.net/bWY7k.png