A network administrator is investigating sporadic connectivity disruptions for internal users accessing external web services through a recently deployed FortiGate firewall running FortiOS 6.2. While some connections are established without issue, others fail intermittently, leading to user complaints about unreliable internet access. The administrator has reviewed the firewall policies and observed the session table, noting that sessions are sometimes being terminated unexpectedly. What underlying FortiOS 6.2 security processing mechanism is most likely contributing to these inconsistent connectivity outcomes?