DX NetOps Performance Management is integrated with Spectrum.
Some but not all Devices added to the Domain based Global Collections (GC) in Spectrum are being synchronized to Performance Center inventory.
An influx of many devices, over 3,000 in this case, were added to Spectrum and synchronized to Performance Center at one time.
As a result of the large number of device additions, it overwhelmed the systems and the synchronization timed out during synchronization cycles after the devices were added to the systems.
Once the timeout struck, devices not yet synchronized would not be until a full synchronization was run.
All supported DX NetOps Performance Management releases
Run a Full Synchronization of the Spectrum Data Source in Performance Center.