Using sass (dart-sass) with css2json-loader acts weird and crashes the app

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 6.4.x (probably happens on older)
• Cross-platform modules: 6.4.x (same)
• Android Runtime: 6.4.x
• iOS Runtime: 6.4.x

Describe the bug
An app with SCSS that is handled with sass implementation (dart-sass) and then served through css2json-loader produces code in the form of "undefinedundefined" inside bundle.js, just after the css2json produced code and app crashes on startup. Removing the css2json-loader and using css-loader works normal. Changing Webpack to 4.40.x produces several pages filled with "undefinedundefinedundefined...".

To Reproduce
Use the provided project and try to run it.

Expected behavior
To run.

Sample project
css2json-loader_sass_issue.zip

首先，使用列出的 NativeScript 版本和 dart-sass 管線執行提供的 css2json-loader_sass_issue.zip 範例。檢查 bundle.js 中 css2json 產生程式碼附近的內容，並將結果與 css-loader 比較；當範例應用程式啟動時不再出現 undefined 文字或當機時，即表示完成。