Hi,
I'm using webpack@^3.5.5, css-loader@^0.28.7 and css-modules-require-hook@^4.2.2.

My hook looks as follows:

hook({
	extensions: ['.less'],
	preprocessCss: function(css, filename) {
		return parseLess(css, filename);
	},
	generateScopedName: '[local]-[hash:base64:5]',
	rootDir: path.resolve(__dirname, '../../../../../')
});

rootDir matches the context of webpack and of css-loader, but the generated hashes do not match.
I'm a bit lost, so let me know what more information I can provide that might help to solve this.