Broken for ubuntu as of version 2.1.5

[kasvtv]

I'm getting errors for versions higher than 2.1.5 on Ubuntu. Rollbacking to 2.1.4 makes it work again:

    ERROR in ./src/components/LoaderBubble/index.scss (./node_modules/css-loader??ref--5-1!./node_modules/postcss-loader/lib??ref--5-2!./src/components/LoaderBubble/index.scss)
    Module build failed (from ./node_modules/postcss-loader/lib/index.js):
    TypeError: Cannot read property 'toString' of undefined
        at Promise.then.res (/home/XXXXXXXXX/node_modules/postcss-node-sass/index.js:35:38)
        at <anonymous>

It crashes for every single file

[arpadHegedus]

I merged a pull request, please double check your issue if it still persists.