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
Working in information security, I see this far, far too often in support tickets from employees who are unable to get to a site because our proxy is blocking misconfigured certificates. Usually we like to reach out to the owner of the site and have them update their configuration, and it gets quite frustrating when we find an unresponsive organization. Having to bypass cert checking for a site on our end is a huge s…
There can be. HTTPS still gives you encryption over the wire. It still protects against a passive eavesdropper, like a casual packet sniffer on a public wi-fi network. The whole certificate deal protects against a Mallory with power to intercept and spoof messages. Of course nobody on the public internet can be sure there isn't a Mallory in or at the edge of the user's ISP, but in plenty of intranet or otherwise controlled networking scenarios, HTTPS with certificates lacking a trust chain can be reasonable.