This works
add_filter('acf/get_field_group', 'hide_field_group_from_clone', 20);
function hide_field_group_from_clone($group) {
//ob_start(); echo 'POST'."\r\n";print_r($_POST);error_log(ob_get_clean());
if (isset($_POST['action']) && $_POST['action'] == 'acf/fields/clone/query' && $group['key'] == 'group_5b586829bb34c') {
return false;
}
return $group;
}