• Please include the raw text output from git, so that we can reproduce the problem:

Δ \dev\null ➔ ..\test.md

• A screenshot of Delta's output is often helpful also:
  

If you enable git config --global delta.relative-paths true, the there's unnecessary /dev/null and arrow to the left of added files, at least for git diff --cached on Windows 10 when the path is relative.