Fatal error: 1048:Column 'value' cannot be null :: insert into sessions (sesskey, ex

[mesnitu]

....don't even know what to ask.... but I'm getting this logs.

What should I be looking for ? this DUPLICATE KEY UPDATE where is it coming from ?

[04-Jun-2016 10:17:22 Europe/Lisbon] 
PHP Fatal error:  1048:Column 'value' cannot be null :: insert into sessions (sesskey, expiry, `value`)
            values ('skc7lplhr8mpjptu72b700uhh3', 1465033282, null)
            ON DUPLICATE KEY UPDATE `value`=null, expiry=1465033282 ==> (as called by) /home/xxxxxxxxxx/xxxx/includes/functions/sessions.php on line 69 <== in /home/xxxxxxxxxx/xxxx/includes/classes/db/mysql/query_factory.php on line 167

Thanks