The available state for the August Doorbell is currently set based on the state of the binary ding sensor. This means that if there is no door bell rings in a while on startup the doorbell is shown as Unavailable (#20421) . This ties the availability of the doorbell to the actual online state thats in the device information retrieved from august so that even if there has not been a doorbell ring activity on a while the device shows as online when it is.