Thanks Jason. The time period of my dahsboard is 30min. If you are saying like down one indicates the history of previous interval. It had never come like above 'X' and below as 'tick' mark even if the previous 30min was fine and current state was errors. It is showing like complete red in that case.
What it shows is whether there is an active incident on the top and if there was ever an incident in the given timeframe at the bottom not just the previous state. So if there is currently an incident, then there is an incident in the timeframe hence the red x on the top and bottom. You'll never see an X in the top and the green tick in the bottom.