Additional icon classes not rendering

Hi again. I'm having a similar issue with the TikTok icon that should be available as a free icon. If I add fa-brands via the inspector it appears, but when adding fa-brands to additional classes field in manage display, the class is rendered but commented out.

Here's what my inspector gets:

<!-- BEGIN OUTPUT from 'modules/contrib/linkicon/templates/linkicon-item.html.twig' -->
<svg aria-hidden="true" class="svg-inline--fa fa-tiktok linkicon__icon icon" focusable="false" data-prefix="fab" data-icon="tiktok" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" data-fa-i2svg=""><path fill="currentColor" d="M448,209.91a210.06,210.06,0,0,1-122.77-39.25V349.38A162.55,162.55,0,1,1,185,188.31V278.2a74.62,74.62,0,1,0,52.23,71.18V0l88,0a121.18,121.18,0,0,0,1.86,22.17h0A122.18,122.18,0,0,0,381,102.39a121.43,121.43,0,0,0,67,20.14Z"></path></svg>
<!-- <span aria-hidden="true" class="linkicon__icon icon fab fa-brands fa fa-tiktok"></span> Font Awesome fontawesome.com -->
<span class="linkicon__text">TikTok</span>
<!-- END OUTPUT from 'modules/contrib/linkicon/templates/linkicon-item.html.twig' -->

> when adding fa-brands to additional classes field in manage display, the class is rendered but commented out.
You need to add fa to Prefix option, and fab fas far, not fa-brands to Additional classes. Please read more the descriptions.

Also:

1. Check your internet. Linkicon doesn't need it, FA likely does.
2. Press F12 for Console, and fix any errors.
3. At FA admin page, switch your option from SVG to HTML, and vice versa. Clear cache and verify in between.
4. Open you FA CSS file, ensure .fa-tiktok is there.

Hope one works :)