Parsing error: E007 & instead of &amp

Parsing error: E007 & instead of &amp

Versions 4.1.4 to 4.1.7 and 5.0.5

E007 Found '&' within 'href'. You should use '&amp' instead:

Error in ../blog/inc/users/model/_user.funcs.php
@version $Id: _user.funcs.php 9 2011-10-24 22:32:00Z fplanque $

Line 297 (Lines 234 and 535) on Version 5

$register_url = url_add_param( $register_url, 'redirect_to='.rawurlencode( url_rel_to_same_host( $redirect, $htsrv_url_sensitive ) ), '&' );

The last &amp was just an & before the hack