Software defect in Extreme Management Center only for ERS devices.
ERS (BOSS) devices would not have the Config Change flag set appropriately. This is resolved in software release 8.4.0 (and above).
The Config Change column as displayed in Network -> Devices will trigger if there has been a detected configuration change in the last 30 days. It will only reset when 30 days of archive has lapsed without a detected configuration change. This applies to all devices including ERS (BOSS) and VSP (VOSS).