name is not being passed to mailchimp, only email

upon buddypress registration on my site, the user's e-mail and group is added to mailchimp, but his name is not.

while i do have a custom field in the buddypress registration, i haven't added a custom field for the name, that is still the default buddypress standard field. also, i tried deleting the custom field i created but that did not resolve the problem.

why is the name not getting passed to mailchimp?