I’ve done some investigating, and the problem is that all the fancy font scripts are loaded on every admin page, not just the plugin settings page. I’ve fixed this by adding the following code at line 474 of events-calendar-templates.php, which limits the scripts to the customizer and plugin settings page:
if(is_admin() && !is_customize_preview() && isset($_GET['page'])){
if(strpos($_GET['page'], 'tribe_events-events-template-settings') === false){
return;
}
}