There is a term you will see here, called "Instant Status". Newer devices tend to have that feature, but some do not. What Instant Status means is that the device will notifiy Vera when its state is changed. Non-instant status devices do not. On those devices Vera will not know about the state change until the device is polled, which can be several minutes later (depending on the polling interval).
If instant notification is needed for a specific device, then that device will need to be replaced with a device that supports Instant Status.
