SourceTree Custom Action on Mac returns "launch path not accessible"

Originating from Community thread - https://community.atlassian.com/t5/Sourcetree-questions/SourceTree-Custom-Action-on-Mac-returns-quot-launch-path-not/qaq-p/803006#M22877

I've seen there are some answered threads, but this still doesn't work for me.

I even tried putting in dummy actions like:

`echo $PATH`

or

`/usr/local/bin/git --version`

and the error is still the same.

I'm using "system git" 

> git version 2.17.0