Same here. I'm on the latest version of the oxwall script (1.8.4) and I'm facing the same issue.
A logged in user that doesn't log out, the next day is asked to re-enter username and password.
Asking credentials to login and show a user online/offline are two different things.
The second thing is the cron job you mention above. After a time interval you show users as off-line.
Now, if I want a user never to be asked again to re-enter username and password (as allyn said like fb does), what changes should I do? How do you keep logged in a returning user? Is it an entry in db that checks login time or just cookies?
Of course "remember me" is checked and this happen with Firefox, Chrome, on windows phone, on iphone, on different devices and laptops etc. So, it's not a browser configuration.
Regards