Hah! While waiting for my name-appropriate cert to deploy for a CloudFront distribution I momentarily accessed the site with an invalid certificate, then clicked the option to undo/disallow that. When checking later, the right cert was in place and there was no having to click through, but the icon still showed a warning. I dug into it, and it said “Valid Certificate”, “Secure Connection”, and then
Active content with certificate errors You have recently allowed content loaded with certificate errors (such as scripts or iframes) to run on this site.
Wow, now that is picky!
Update: I wonder if it said that because it was using a cached bit of content from when I used the invalid cert…that would make sense, but I’ve nagivated on so I can’t check that. But the warning has cleared after some time.