Re: Tiki attaching :80 to HTTPS URLs
In tiki17 the issue persists and the following serves as workaround for me:
global $base_url_https;
$base_url_https = str_replace(":80", "", $base_url_https);
$base_url_http = str_replace(":80", "", $base_url_http);
$base_url = str_replace(":80", "", $base_url);
in tiki-setup.php, insert around line 304