Issue Pulling Leader Info

I’m having trouble pulling the main_leader data into the post_meta section.

I’ve tried

function ccb_core_customize_group_fields( $post_type_maps ) {
	if ( ! empty( $post_type_maps['ccb_core_group']['fields'] ) ) {

		$post_type_maps['ccb_core_group']['fields']['main_leader'] = 'post_meta';
        $post_type_maps['ccb_core_group']['fields']['leaders'] = 'post_meta';
	}
	return $post_type_maps;
}
add_filter( 'ccb_core_synchronizer_post_api_map', 'ccb_core_customize_group_fields', 20, 1 );

As well as

function ccb_core_customize_group_fields( $post_type_maps ) {
	if ( ! empty( $post_type_maps['ccb_core_group']['fields'] ) ) {

		$post_type_maps['ccb_core_group']['fields']['main_leader']['full_name'] = 'post_meta';
        $post_type_maps['ccb_core_group']['fields']['main_leader']['email'] = 'post_meta';
	}
	return $post_type_maps;
}
add_filter( 'ccb_core_synchronizer_post_api_map', 'ccb_core_customize_group_fields', 20, 1 );

The only one that creates a field is Leaders but the value comes out blank.

Any guidance would be helpful. Thank you!