CommandCentral Enterprise Reporter reports duplicate device entries.
CommandCentral Storage assigns a unique identifier (UUID) to each device it discovers. If a device is undiscovered for seven days, CCS removes it's entry from the database. If after seven days the device is rediscovered, CCS will assign the device a new UUID. CCER will see the new UUID and treat the device as a new object.
This behavior is as expected from CCER. To confirm that the duplicate entries have different unique identifiers, insert the column "Unique Identifier" to the CCER report in Report Studio.
The path to find the "Unique Identifier" object is:
Array Analysis > Array Analysis > Array Analysis Views > By Array Attribute > By Array Attribute > Array > Unique Identifier