Multiple Set-Cookie in header? Session regenerating maybe?

The only thing I could find is our upgrade from CodeIgniter 2 to CodeIgniter 3.

LOL That is a big change! Did you follow the upgrade guide?

Upgrading from 2.2.x to 3.0.x

Step 6 of the guide is about Session library

I've made sure that I followed all steps. Everything with the session works except for this part.
This is the config for session used

Code:

$config['sess_driver']          = 'database';
$config['sess_cookie_name']    = 'ci_session';
$config['sess_expiration']    = 7200;
$config['sess_use_database']    = FALSE; //TODO SET TRUE IN LIVE
$config['sess_table_name']    = 'Ci_sessions';
$config['sess_match_ip']    = FALSE;
$config['sess_time_to_update']  = $config['sess_expiration'];

If you followed all the steps, you wouldn't have 3 of these settings.
Hint: you aren't even using 2 of them.

The session ID lengths are different ... if it was CI_Session setting both, that wouldn't be the case.

I don't undestand what you mean.

The first Set-Cookie header sets a 40-character ID - that is sent by CI.
The second has a 32-character ID - that is NOT what CI sends; something else is causing it.

Could it have something to do with this: https://github.com/bcit-ci/CodeIgniter/i...-193412960

Entirely possible.

Thanks for the update. I kind of now know where to search. 

I've missed the session config options. I've changed them and they look like so now.

Code:

$config['sess_driver']          = 'database';
$config['sess_cookie_name']        = 'ci_session';
$config['sess_use_database']    = TRUE;
$config['sess_save_path']        = 'Ci_sessions';