Devices in or exiting Maintenance should continue to correctly report their connection status correctly

Per SI-497717: Device Mangement's "Device Status" panel briefly but incorrectly shows "Send connection" status as "offline" when exiting Maintenance we are raising this minor bug since it apparently requires a significant overhaul to the way Maintenance mode operates.

Steps to reproduce the original observed bug:

• Connect a device to Cumulocity, actively sending data

• Set a “Required interval” for the device - e.g. 2 minutes

• Switch the “Maintenance” toggle switch; observe the icon change to an orange spanner.

• The “Last communication” time freezes at the time of the last message received prior to the setting of Maintenance - but the device is still communicating. In our view, the “Last communication” time should continue to be updated.

• Switch the “Maintenance” toggle switch back

• The device is still communicating, and remains communicating, yet a default of “Not communicating” is assumed for the “Send connection”

• After the “Required interval” (in this case 2 minutes), the connection status resets to “Online”

• Note that no c8y_UnavailabilityAlarm is generated during this period, which is inconsistent with what the Device Status displays during that time.

In our view, this is a minor bug - what should happen is:

• The “Last communication” time should always be updated - regardless of the Maintenance status

• When Maintenance is switched off, the panel should immediately check if there has been a Send event in the last “Required interval” period, and if there was, set the “Send connection” icon to green/Online immediately.