More "invalid security tokens".

This subject has come up before (including by me). The CSRF token fails to validate. It's often a caching problem that goes away but it shouldn't happen at all when logging on. 

Now I am adding multiple CB login modules ( because each redirects to a different GJ group ), and I seem to be getting the invalid token error more often.

When this happens I have to refresh the page and log in again, which always works, but I shouldn't have to do that. It's annoying.

Disable Joomla's page cache plugin. That's typically the only culprit. We don't decide when a token expires. We simply call Joomla's API to give us a token. What Joomla version are you using?

Additionally sometimes this can happen if the user is on www version of your site, but you have the live_site configuration option configured in configuration.php without www. That causes a cross domain post and will fail. It's best to leave live_site empty or ensure they always remain on the domain of your choosing using htaccess redirect/rewrite rules.