There is conflict with icon font, T4 uses FontAwesome while com_cck utilizes IcoMoon, I updated custom CSS to fix it:
.com_cck [class^="icon-"]:before, .com_cck [class*=" icon-"]:before {
font-family: 'IcoMoon' !important;
}
div.cck_forms.cck_site div.cck_form span[class^="icon-"], div.cck_forms.cck_site div.cck_form span[class*=" icon-"] {
margin-right: 0.25em;
}
Kindly check.