Alarm Management KPI display
These alarms have once existed and made footprint in the Alarm Analysis. They will persist in the statistics until the next analysis Period.
I suggest adjusting the Alarm List filter used in the Alarm Analysis and exclude undesired categories, etc from being included in the KPI calculation.
Deleting an alarm does not affect the KPIs. Never use Delete Alarm to clear an alarm unless it is proven to be truly stuck. If source server support OPC AE Refresh there is even more arguments against using Delete Alarm since the deleted alarms will reappear at next refresh.
Improve your filter settings.