function my_wpf_forms_args( $args ) {

    foreach ( $args['update_data'] as $crm_field => $value ) {

        if ( $crm_field == 'email' ) {
            $args['email_address'] = $value;
            break;
        }

    }

    return $args;
}

add_filter( 'wpf_forms_args', 'my_wpf_forms_args' );