git diffn --color-words fails

[ElectricRCAircraftGuy]

Try it out and you'll get this:

============== GIT DIFFN ERROR ==============
THIS CODE SHOULD NEVER BE REACHED! If you see this, open up an issue for `git diffn`
  here: https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles/issues
  It may be because you have some custom `git config` color or text formatting settings
  or something, which perhaps I am failing to handle correctly.
Raw line: 
=============================================

My goal was to try to get git diff to highlight on a char-by-char or word-by-word basis instead of on a line-by-line basis, and I came across and tried this: https://makandracards.com/makandra/28067-git-diff-per-word-or-character.