Hello! Did you figure this out? I'm experiencing a similar issue on one of my clients' sites. Non-cached, first visit to the HTTP version of the URL is not force-redirecting to HTTPS on Safari (mobile and desktop) and Firefox. We're getting a "Not Secure" notice in the address bar. The HTTPS version of the URL works fine. I've contacted Squarespace support, but it's been more than a week and they have not fixed it. Any suggestions would help, thanks!