The 'Instance' Realtime availability dashboard does not show an outage period for an instance during a planned maintenance change even though the instance was not available for a short period.
The RealTime availability dashboard (KB0547242) for instances will not show an outage period for any changes that are part of a planned maintenance.
If a maintenance process runs past its Planned End Time, then a P1 Case should have been raised on HI, which will have an 'Outage Type' of 'Unplanned Outage'. This outage type in conjunction with the 'Impact Duration', will filter through to the RealTime dashboard and show as an 'outage'.
If however the maintenance executes successfully within the planned window, even if there is outage , this is not expected to show on the RealTime dashboard.
Any outage outside of or not related to any change, is expected to show on the RealTime dashboard.