add_query_arg function doesn't remove the empty '?' when an anchor exists

[benjamin.anakena]

To reproduce:

<?php
$url = 'https://domain.com/uri?param=value#anchor';
$url = add_query_arg( 'param', false, $url );
echo $url;

Expected value: https://domain.com/uri#anchor
Returned value: https://domain.com/uri?#anchor