PHP Session lifetime
as discussed on the phone, there is an issue with FLOW3's session lifetime. FLOW3 uses the PHP Session, by default. Thus, session behaviour is influenced by the
php.ini configuration. Therefore, the session garbage collector removes sessions every 24 minutes (based on some probability parameters). And it seems, that up to now
TYPO3.FLOW3.session.inactivityTimeout doesn't set the
session.gc_maxlifetime of PHP to make longer session lifetimes possible.