The Site Collection Statistics List within the ControlPoint Configuration Site shows site collections that no longer exist in the farm.
The Site Collection Statistics List within the ControlPoint Configuration Site is a list showing environmental statistics for all site collections in a farm. It is updated every night during discovery and the data is pulled from the xcSiteInfo table in the xcAdmin database (the ControlPoint Database). As that database contains information about ALL site collections in the farm, including removed ones, some entries may be retained in the Statistics List after the site collection has been deleted.
Starting in ControlPoint version 5.2, a parameter can be added in the ControlPoint Settings List that will remove all entries in the xcSiteInfo table for site collections that no longer exist in the environment. NOTE: This will permanently delete data within the xcSiteInfo table within the xcAdmin database and the ability to report on legacy site collections will be removed.
Parameter Name: RemoveLegacySC
	Parameter Value: true
	Category: Special Purpose