The unmanaged endpoint widget in the Apex Central dashboard is mainly used for Apex One agents and does not include the detection of the existence of a Deep Security agent on the machine. This means that even if there is a Deep Security installed on the server, it will still be counted as an unmanaged endpoint.
The number of unmanaged machines on the Apex Central console is calculated as the total number of AD computers minus the managed computer count. The scope selected by the customer, whether it is Network or a specific date and time, can also affect which machines are visible under Unmanaged Endpoints.