Mailchimp Marketing API not returning all subscribers from list

Question

I'm dealing with a problem retrieving subscribers from a Mailchimp list. I am using the official PHP Mailchimp Marketing API library and Codeigniter.

Here's my code:

private function getMailchimpListSubscribers(string $list, int $count, int $offset)
    {
        $response = $this->mailchimpMarketing
            ->lists
            ->getListMembersInfo(
                $list,
                null,
                null,
                $count,
                $offset,
                null,
                'subscribed'
            );

        if ($response) {
            log_message('error', $response->total_items);
            return $response;
        }
    }

    private function getProductionSubscribers(string $list = 'test'): array
    {
        $finalTos = [];
        $count = 1000;
        $offset = 0;

        do {
            $tos = $this->getMailchimpListSubscribers($list, $count, $offset);

            if (!empty($tos->members)) {
                $finalTos = array_merge($finalTos, $tos->members);
            }
            $offset = $offset + $count;
            log_message('error', $offset);
        } while ($offset < $tos->total_items);

        $callback = fn($member) => [
            "email" => $member->email_address,
            "type" => "to"
        ];
        return array_map($callback, $finalTos);
    }

Using the logging, I can see that the offset and the total items are working as expected. Offset is increasing until the max number of members on the list.

ERROR - 2023-07-18 08:53:59 --> 2651 <--total_members
ERROR - 2023-07-18 08:53:59 --> 1000 <-- offset
ERROR - 2023-07-18 08:54:17 --> 2651
ERROR - 2023-07-18 08:54:17 --> 2000
ERROR - 2023-07-18 08:54:32 --> 2651
ERROR - 2023-07-18 08:54:32 --> 3000

However, I always get 1001 items but not the full list.