After upgrading an Information Exchange/HealthShare instance that has a registry namespace, you may notice that the Caché audit log gets filled with frequent login failures by the HS_Services user (check this by going to Management Portal > System Administration > Security > Auditing > View Audit Database). Clicking the “details” shows event data like:

Error message: Access Denied
CSP Application: /csp/healthshare/hsregistry
Authentication: Delegated