It sounds as if you were connecting directly to your machine. Origin certificates are only valid in a proxied context. Did you unproxy or change something locally?
The domain is properly configured and goes via the proxies, so the Origin certificate should never be presented to the client. Loading the site also shows the right certificate.
This must be a local issue on your end. Either your DNS resolver has some outdated value or you made some changes on your machine to reroute requests. I’d check for that first.