Context

You may notice in your device event logs that there are two consecutive device.disconnected events for the same device without any device.connected event occurring between them. This can appear unusual and may trigger multiple offline device tasks or alerts in your system.

Answer

This behavior occurs when a device experiences a two-stage disconnection process. Here's what happens:

1. Stage 1 - Device Disconnection: The lock itself goes offline while the hub/bridge remains online. This triggers a device.disconnected event with error_code: "device_disconnected".

2. Stage 2 - Hub Disconnection: Later (typically within an hour), the hub/bridge also goes offline. This triggers a second device.disconnected event with error_code: "hub_disconnected".

Our system treats these as distinct disconnection conditions because they represent different failure points in the device connectivity chain. The device-level disconnection and hub-level disconnection are tracked independently, which is why no device.connected event occurs between the two disconnected events.