When setting the proxy settings via the gui the env variables are added to the file in all lower case which the unity app doesn't pick up on.

-repro:
--build scene that uses the www class to get something from the net
--make a linux build
--under ubuntu: enter http + https proxies under System Settings > Networking > Proxies
--open etc/environment and see lowercase variables
--start wireshark and start capturing
--run unity app
--NOTICE unity app not using the proxies
--edit variables to all upper case
--run unity app again
--notice it now using the proxies