I recently: Specified a home directory path for a user in /etc/passwd with spaces in it? but now my .bashrc doesn't source properly when I open a Ubuntu 16.04 LTS WSL window, so I have to source it manually...which works with source ~/.bashrc, but curiously does not work with source $HOME/.bashrc, but oddly does work with source "$HOME"/.bashrc.
So Jeff on the previous question thought that maybe the issue is that something else is sourcing it without the quotes around it.
In fact a similar issue caused me to fork git hub project in which a similar error was occurring; I attributed it to be because I was using mingw64 / git-bash for Windows, but that wasn't the issue at all because now it's occurring in WSL...er at least I think that's the case...