Thanks for your patience.
We were able to investigate and there looks to be an issue with how JFBConnect tries to pre-fill some fields and hide them. This causes JFBConnect to skip an important step, which then causes EasySocial to think the user didn't fill out the fields.. which redirects them back to the beginning of registration and a loop ensues.
To fix, can you please edit the following file:
/plugins/socialprofiles/easysocial/easysocial.php
Around line 142, you should see:
Update 'true' to 'false, like:
Test registration again and let us know if the registration flow works as expected.
We'll investigate if any other changes are needed as well.
Thanks,
Alex