Issue with session since upgrade to v3.1.9

Hi there,

I notice issues with the session since I upgraded to v3.1.9.

This is the issue:

Severity: Warning --> session_start(): Failed to decode session object. Session has been destroyed /CI_APP/system/libraries/Session/Session.php 143

These are my session settings: 

$config['sess_driver'] = 'files';

$config['sess_cookie_name'] = 'tp_session';

$config['sess_expiration'] = SESSION_DURATION;

$config['sess_save_path'] = null;

$config['sess_match_ip'] = false;

$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = false;

Anyone else having this issue as well?