Successfully generated a CSR and got the Cert back and installed through Certificate Manager - That seemed to work fine.
Go into System Admin and try to select it and it hangs like this:
But what is interesting is it actually successfully installs the cert - when I go to the box, via https, it shows the correct cert.
When I go back into System Admin and go back into HTTPS Settings -> Settings, I get this:
Along with this:
System Admin 13.0.71.2 - Certificate Manager 13.0.34.4