Sometimes Anti-Passback status doesn't show the actual status when a user does not actually enter the gate after successful authentication.
BioStar 2 has an additional option using the door status(Door sensor) to show the actual Anti-Passback status.
With the option enabled, your Anti-Passback zone considers two factors; 1. Authentication, 2. Door sensor.
i) Door setting
ii) APB zone setting
Device 1 with 'Use Sensor when Entry Confirmed APB enabled' ON
The APB alert is not triggered even when you authenticate without the exit door authentication until the door opened/closed.
Device 2 with 'Use Sensor when Entry Confirmed APB enabled' OFF
The APB alert is triggered even if your door was not opened.