Symptoms:
Aria Automation 8.16.2 and above
With version Aria Automation 8.16.2 changes were implemented to which help to identify the VM and try to match to them to the correct deployment.
In such case you may not see the VM as discovered, but the VM references for the existing deployment have been corrected and any Day-2 Actions should work as expected.
However there may be corner cases which would still show the same VM as "Discovered".