Hi,
As you say google is not supported on the free janrain social sign in, this site is using a paid pro account which is why it was still available to us.
I just went in to my janrain dashboard and enabled google plus which required me to disable google because they only allow one or the other. They recommend using google plus since it encompasses other google accounts and allows more people to sign in so I went ahead and dropped google and added google plus. As it says on their dashboard page if you make changes to the providers in your widget it can take up to one hour before those changes appear in widgets that are already deployed (this can explain why a new widget in a test page worked but the already deployed widget did not). At first I configured it with a google client id that I had setup previously for other purposes but when it finally appeared in the widget on this site about an hour later and I tried to login it gave me an error about the application name being missing and I was unable to login so I went back and created a brand new client id for a web app in the google cloud console and after waiting another hour to make sure it was updated this time it did work just fine.
So as far as I can tell it is working correctly.
The only thing I noticed different in the latest widget code vs what we had is that we had this:
if (typeof window.janrain !== 'object') window.janrain = {};
window.janrain.settings = {};
but the latest widget code had this:
if (typeof window.janrain !== 'object') window.janrain = {};
if (typeof window.janrain.settings !== 'object') window.janrain.settings = {};
I'm pretty sure this was not the cause since the widget would need settings to work at all and it was working, but I have updated the source code to match the latest widget so if you continue to have problems you could get the latest mojoportal code and see if it does make any difference for you.
Hope that helps,
Joe