steal{ loaded: 'production.css' } not working

I am using the latest steal from github.
In production mode I load production.css in the head.

I try to tell steal not to load production.css like so:

steal = {
        env: "production",
        loaded: ["amo/production.css"],
        production: "amo/production.js"
    };

I tried different settings, but the production.css is always loaded twice in production mode.

Is it not possible anymore to tell steal not to load the production.css this way?

Jochum.