Requesting a URL of http://hostname/static/hello.png, with the nginx config's static 'root' directive value set originally as '/app/static/', seems to result in nginx incorrectly looking for '/app/static/static/hello.png' (i.e. nginx appends the URL's path to the root directive's value); resulting in 404.
Requesting a URL of http://hostname/static/hello.png, with the nginx config's static 'root' directive value set originally as '/app/static/', seems to result in nginx incorrectly looking for '/app/static/static/hello.png' (i.e. nginx appends the URL's path to the root directive's value); resulting in 404.