The complexity here is that, by default, a superseded patch has its relevance changed so that it will appear to be “Not Relevant” in order to maintain faster client performance. It’s not possible for the reporting integrations to determine whether the fixlet became “Not Relevant” because the patch was installed, or because the patch was superseded and the fixlet was modified to coerce the “false” result.
You can configure your endpoint to continue evaluating these superseded fixlets with the “enable superseded evaluation” client setting described at Pre-Announcement: Superseded patch changes for Patches for Windows , but understand that this can have some impacts on client performance (as the client will spend time evaluating superseded fixlets that should no longer be deployed). But that should at least give an idea of how many older/superseded patches are still missing from the server.