Database Sessions losing Userdata?

I'm trying to determine if this is something wrong in my setup or a possible bug in CI3. I'm working on a checkout process for a site in CI3. We're using database sessions, and - in this case - the Cart library. I'm seeing that during the session ID regeneration, it's creating the new session, but failing to transfer the existing userdata over (in this case - the contents of the cart). sess_regenerate_destroy is false, so it should keep the data.

Is anyone else experiencing this?

Code:

$config['sess_driver'] = 'database';
$config['sess_cookie_name'] = 'id';
$config['sess_expiration'] = 7200;
$config['sess_save_path'] = 'ci_sessions';
$config['sess_match_ip'] = true;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = FALSE;

Support Development •  CodeIgniter 4 Foundations • Practical CodeIgniter 3  • CodeIgniter Tutorials