BUG: Loaders (css-loader + style-loader) can generated different modules ending with identical relative paths (`./node_modules/PKG/FILE.css`)

Thanks for the great plugin!

This is my configuration:

```javascript
new DuplicatesPlugin({
emitError: true,
verbose: true,
}),
```

This is the output I get:

```
WARNING in Missing sources: Expected 22, found 0.
Found map: {}

Duplicate Sources / Packages - Duplicates found! ⚠️

* Duplicates: Found 22 similar files across 22 code sources (both identical + similar)
accounting for 219534 bundled bytes.
* Packages: Found 0 packages with 0 resolved, 0 installed, and 0 depended versions.

* Understanding the report: Need help with the details? See:
https://github.com/FormidableLabs/inspectpack/#diagnosing-duplicates
* Fixing bundle duplicates: An introductory guide:
https://github.com/FormidableLabs/inspectpack/#fixing-bundle-duplicates
```

I guess this is some bug that it doesn't show me what the duplicates are. Also, there are some missing sources but I don't know where these come from.

How do I debug this?