Hi,
You need to find the code that is adding that social icons and change data-x-icon to data-x-icon-b to resolve the issue.
You can check first in your child theme’s functions.php file
As of Font Awesome version 5.x, they split icons into multiple fonts. This can be fixed by changing instances of the data-x-icon attribute to one of the following:
data-x-icon-b for social icons.
data-x-icon-o for outline icons.
data-x-icon-s for solid icons.
The original attribute data-x-icon will still work for solid icons as a fallback but we’ve updated everything for consistency.
Hope that helps.