TYPO3 Core

If a session of FE or BE is configured to run on a lifetime basis (not the default session basis), the expiration date does not get refreshed with a request, causing the cookie to expire after X seconds nevertheless a user was active or not.

In out setup, we run the following configuration:

$GLOBALS['TYPO3_CONF_VARS']['FE']['lifetime'] = 3600;
$GLOBALS['TYPO3_CONF_VARS']['FE']['sessionDataLifetime'] = 3600;
$GLOBALS['TYPO3_CONF_VARS']['FE']['permalogin'] = 2;

In the current case, the cookie expires after 3600 seconds without any chance to refresh the expiration date.