Have never experienced that before, continued for about 5 minutes after I posted and occurred almost instantly after I posted the question (I tried to make an immediate edit and chrome blocked it because of the https issues).
Do you use any certificate-related extensions? If not, you may want to install one that compares certs to those seen by others, just to see if anything interesting occurs. Also, check for any unexpected trusted CAs. I've seen a system infected by malware that adds a CA that was signed by a leaked Microsoft key.