TL;DR: bing SSL certificate is wrong. https://bing.com : subject=/CN=*.bing.com https://www.bing.com : subject=/C=US/O=Akamai Technologies, Inc./CN=a248.e.akamai.net
Companies! Make sure your certs are all in order! There's no reason to send a page to your users over HTTPS if they can't trust the certificate. Canonical has been a long-time offender of this, with many of their pages sporting a certificate signed to canonical.com but being served by ubuntu.com.