Movere will "age-out" data that is greater than 31 days old as new data comes in, regardless of the source of the new data.
So, for example if you scan different segments of the customer's environment e.g. Domain A and Domain B. And you scan Domain A first and then stop scanning Domain A and take a break before scanning Domain B.
Movere updates the Days Since Last Activity date for the whole data set including the earlier Domain A scans when Domain B is scanned.
So when the Days Since Last Activity date exceeds 31 days, Movere flags these machines as Retired. This will remove the machine from all Azure sizing views, but does not lose the data.
In order to update the state from Retired to Active, simply rescan the impacted devices! We highly recommend scheduling periodic AD scans in order to continually update all Active device's Last Activity date.