Trouble with special chars in domain name

Hi

i got a domain with danish letter: ?, hj?rringavis.dk

and when i try to access image.php, it redirects in a never ending loop.

i found out what causes the loop, in file: wp-includes/canonical.php:499

if ( $do_redirect ) {
// protect against chained redirects
if ( !redirect_canonical($redirect_url, false) ) {
wp_redirect($redirect_url, 301);
exit();

and if i do a :
print “$redirect_url, $requested_url”;die;

i get:
https://www.hj?rringavis.dk/2016/01/26/ib-groenbech-paa-vej-med-ny-cd/ib-gronbech_600x250/, https://www.xn--hjrringavis-hgb.dk/2016/01/26/ib-groenbech-paa-vej-med-ny-cd/ib-gronbech_600x250/

So i guess it redirects because its not the same domain?
I have also tried to change the site_url variable to https://www.xn--hjrringavis-hgb.dk with no difference, std value: https://www.hj?rringavis.dk

so at this moment, i fixed it by putting a “return” before the redirect, but i would like to know if there is a correct solution, or if its a bug.