Emberjs: Failed to find a valid digest in the 'integrity' attribute

I'm trying run an Ember project locally : http://ift.tt/2gEgEri. I'm using pycharm 2017 using git-bash as my terminal in win7. I have npm and node installed along with the jetbrains emberjs plugin.

I can start the server using :

  $ COSMIC_BUCKET=your-bucket-slug npm start

  > cosmicrealestate@1.0.0 start C:\ember-real-estate-website
  > node server.js

When I open the browser I see nothing. In the console:

Failed to find a valid digest in the 'integrity' attribute for resource 'http://localhost:3000/assets/vendor-969213113bf8ce8653053cf775905b0d.css' with computed SHA-256 integrity 'X3XPwk5BB1JgnemiDQkQoHJwfotEk8I6G1p+XYvKfiw='. The resource has been blocked.

How can I fix this?