Phorge currently ships FontAwesome version 4.7.0 from 2016, located in https://we.phorge.it/source/phorge/browse/master/webroot/rsrc/externals/font/fontawesome/
Firefox console complains that "Glyph bbox was incorrect". This issue was fixed in https://github.com/FortAwesome/Font-Awesome/issues/19925 and requires at least version 6.5 of the Font Awesome available at https://github.com/FortAwesome/Font-Awesome under https://fontawesome.com/license/free