At present, you only receive presence updates for a MiVB ‘Generic SIP Device’ when:

1) a call is made (busy)
2) a call is received (busy)
3) when a call is dropped (available)
4) when the device is signed into the SIP extension (available).

There is no presence update when the device is signed out. This is confirmed 'design intent' by Mitel. That means in the last presence update is 'Available', the device will remain available via API, even after signing out.

Please add SIP de-registration/out of service events to the CloudLink Notifications/Presence API so that SIP device presence can be tracked accurately.