scss sourcemaps stopped working after upgrade from 1.4.5 to 1.5

[sunew]

Versions

<!--
Output from: `ng --version`.
If nothing, output from: `node --version` and `npm --version`.
  Windows (7/8/10). Linux (incl. distribution). macOS (El Capitan? Sierra?)
-->
Angular CLI: 1.5.2
Node: 8.2.1
OS: linux x64
Angular: 5.0.1
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

@angular/cli: 1.5.2
@angular-devkit/build-optimizer: 0.0.33
@angular-devkit/core: 0.0.20
@angular-devkit/schematics: 0.0.36
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.8.2
@schematics/angular: 0.1.5
typescript: 2.4.2
webpack: 3.8.1

Repro steps

• create an app with global styles:

in .angular-cli.json:

      "styles": [
        "styles/styles.scss"
      ],
      "stylePreprocessorOptions": {
        "includePaths": [
          "styles"
        ]
      },

• ng serve --extract-css --sourcemaps

Observed behavior

With angular-cli version 1.4.5 we see sourcemaps in chrome dev tools - see attached image 1. The sourcefile-links points to the original scss file and linenumber from the styles folder (the styles folder defined in .angular-cli.json).
For instance: _footer.scss:47

With angular-cli version 1.5.2 there are no scss sourcemaps - source links points to the css bundles - see attached image 2

<!-- Normally this includes a stack trace and some more information. -->

Desired behavior

scss sourcemaps as in 1.4.5

Mention any other details that might be useful (optional)

[JohnAnthony]

I had what I believe to be a related issue with even getting scss to compile; perhaps @angular/cli has changed how it handles node-sass dependency.

Manually installing the node-sass dependency at the latest version fixed my issues, so it might help you also.

npm install --save node-sass@latest

[sunew]

@JohnAnthony thank you for the hint! It did not solve the issue though.