Why aren't some devices in the Deployment Manager discovered devices node showing as managed when I know that they are because they are reporting inventory regularly using the Deployment Manager for managed devices software?
The 'Managed' column in discovered devices takes its value from the NetworkDevice.IsManaged field where 1 is managed and 0 is unmanaged.
This value gets set in the following scenarios:
During Adoption, the IsManaged field is set to 1 when it is successful
When the daily database maintenance task (see below) runs it sets the IsManaged field to 1 for all devices that have reported inventory recently that have 'managesoft for managed devices' installed.
The daily maintenance task is run by the SQL Server Agent which can be viewed in SQL Server Management Studio, when you expand this section in Management Studio there should be a "Jobs" sub-section and this will contain "Deployment Manager daily database maintenance" and this will run the Stored Procedures PopulateNetworkDevices and UpdateNetworkDevices which will set the IsManaged value.
If you have devices that are not showing as managed but are reporting inventory then make sure that the SQL Server Agent has started and that the daily maintenance is running (check the Job properties to see when it was last executed).
If the job is running but devices still show as unmanaged then contact Support and quote this article advising that you have checked the Agent and job status.