Sorry, yeah it was 4.2 (upgraded to 5) and I’m running WordPress 4.6-RC1 on Heroku.
I’m unsure as to what is causing the issue, however logging-in this morning produced the port number 58076 – whether that’s of any use I’m not sure.
I removed the following (commented) code, pushed to Heroku and it’s not happening anymore
// port is prepopulated here sometimes
if ( strpos( $_SERVER['HTTP_HOST'], ':' ) === FALSE ) {
$url .= in_array( $_SERVER['SERVER_PORT'], array('80', '443') ) ? '' : ''; /*: ':' . $_SERVER['SERVER_PORT'];*/
}
Hope that helps