Clients cannot access the nameservers by clicking (as well as some other settings for the domains such as registrar lock, etc.). Sometimes I can load the page by "right clicking" on the nameservers link and opening it in a new tab. I'm not certain how far this extends but I have a client right now trying to make changes to his domain names.
I've disabled all plugins and the issue persists. I've changed the theme and the issue is resolved. I've also used the current theme without the integration and it works flawlessly. Somehow, this is an issue between the theme we are using and WHMCS integration. I'm guessing it's some kind of conflict? Anyhow, would love some help.