I have been unable to get CMC to pass along first name, last name and one other CB custom field during registration. This is using the community builder plugin. I have mapped the fields as described. I have also now removed the custom field from mail chimp and updated the CB plugin, still no help, I removed field mapping, no help.
I have tried with all fields required and then again not required.
There is one set of check boxes, but they work correctly.
The contact always comes into mailchimp, just no first name, last name, or the custom CB field.
A standard signup box were you manual fill in info works fine.

Where do go from here?
This is on a test site.

thanks
David DeWitt