Demonstration

demo with v5, which is ok, have two messages in console:
SystemJS bundle file loaded!
Nice to see you, world

Actual Behavior

When I update package to latest version (6.10.2) and run scripts:
npm run deploy
npm run www

In browser (http://localhost:3000/) I have doubled message:
Nice to see you, world _bundle-system.js 48:21_
SystemJS bundle file loaded! _index.js:6:12_
Nice to see you, world _bundle-system.js 48:21_