Hi,
This is caused by profile mismatch due to the limited ability of allowing user to select a profile.
After investigating and discussing with the team, we've decided to remove the ability for user to select a profile. Admin will have to set it at backend -> EasySocial -> Settings -> Registration. If default profile is selected, then user will be registered under the currently set default profile.
I've patched this on your site and it should be working properly now.