Plugin does not recognise change of Template from within WHMCS

Changing the Template from within WHMCS Setup > General Settings > General > Template doesn't have any affect on the plugin.

For example. If I change it from Portal (which it should be) to Default I don't see the plugin break or any styling changes. I do see the template changing at my WHMCS installation url.

I've tested this in the base 2012 theme and the problem still exists.

Eg: digitalessence.net / billing shows the default WHMCS template.

and I would now expect the WHMCS/WP integration to break which it doesn't:
digitalessence.net/ client-area

It used to to this. I've tried disabling the plugin/activitaing it, changing my WP themes etc.