Extension not working on basic HTML + CSS file project (includes reproduction steps)

Unfortunately, this extension is not working for me even on a basic project with a single HTML and CSS file. I've re-cached CSS class names after adding the test.css file. I also disabled all extensions for my workspace to confirm nothing else was clashing with this extension, and that also did not work.

Are there logs where I can debug what is going on (if something is crashing, for instance)?

My index.html file is this:

<html>
    <head>
        <link href="test.css" rel="stylesheet">
    </head>
    <body>
        <h1 class="">Hello world</h1>
    </body>
</html>

And my test.css file is this:

.test {
    background-color: red;
}

Here is a screenshot of the suggestions I'm receiving:

My only workspace settings are to disable the "Show Words" suggestions in the editor:

{
    "editor.suggest.showWords": false
}

More details

OS: macOS 12.0.1 Monterey
VS Code version: 1.62.0
Extension version: 1.20.0

zignd / HTML-CSS-Class-Completion

Extension not working on basic HTML + CSS file project (includes reproduction steps) #367