Webpack Firefox Source Map Error

npm run:extract-text-plugin produces SCSS source maps working in Firefox Developer Tools.
npm run:style-loader produces SCSS source maps which do not work in Firefox Developer Tools and print some errors in the console.

Name		Name	Last commit message	Last commit date
Latest commit History 3 Commits
src		src
.babelrc		.babelrc
.gitignore		.gitignore
README.md		README.md
package-lock.json		package-lock.json
package.json		package.json
webpack.common.babel.js		webpack.common.babel.js
webpack.extract-text-plugin.babel.js		webpack.extract-text-plugin.babel.js
webpack.style-loader.babel.js		webpack.style-loader.babel.js

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