Accessing Horde Webmail via SSL

[albans]

I just updated Plesk 7.5.4 to 8.0.0, and now, when I access Horde via SSL it gets error on some sections due to strange URLs.
As if Horde was adding the port 80 to some URLs in the webmail...

So when accessing to
https://webmail.mydomain.com
it gets to
https://webmail.mydomain.com:80

=> this doesn't work as SSL is on 443...

Why is it adding the ":80" after the domain?!

 

[NETSource]

I get similar, but only on some domains - others it appears to work fine.

When I copy the entire URL (https://domain/imp/mailbox.php?page=1) I'm able to get in just fine. Very odd why SSL is forcing the redirect. Is this a new setting?