This KB article outlines the reconciliation of Spectrum devices that are manually discovered in CAPM
As an example, a few devices have been added to CAPM and they now need to be mapped to a custom group based on their Spectrum global collection membership.
For instance - ClientA_rtr1 was discovered manually into CAPM. This router is also present in a Spectrum global collection called ClientA.
In CAPM, under Groups > Inventory > Data Sources > Spectrum > All Global Collections, the "ClientA" global collection is shown but the manually discovered device ClientA_rtr1 does not show up there
Here is in general, how the sync between CAPM and Spectrum works:
Any other GC in Spectrum that contains these devices in IP Domain GC are also synced BUT only the devices/interfaces from the IP Domain GC, not ALL the members of the GC.
Once you add devices to the "Default Domain" global collection in Spectrum, they appear in the CAPC groups as well.