Hi Patrice,
Something messes up the FontAwesome icons.
It might be caused by different things, but it is not a template-related issue.
It might be caused by a 3rd party extension that you have installed. It might be caused by a browser extension/plugin or browser cache and cookies (try with different browser).
It might be caused by your ISP (Internet provider). Try on another computer at different location with different ISP.
For more details, you might want to have a look at all the comments in
this discussion.