session expires earlier on community auth

I have started to the community auth for my project, very easy set up if just follow the instruction carefully.

Thanks to the great work, the basic functions work well.

I only found out a small issue, which I don't know if your guys also experienced. The $config['sess_expiration'] doesn't work exactly same as the seconds I set. For example, if I set this variable to 604800 (7 days/ a week), I found the session timed out around the 3rd day.


I am using CI 3.1.0

Allen