What is the computer telling me at the odometer window when I start the car?

What is your question?

I've just noticed that after fueling my gas tank and starting the engine, I have to wait for the odometer to either reset or finishing displaying a (lighting bolt symbol) followed by a set of descending/ascending numbers before I can reset the trip/odometer I've owned the car just over a year now and this just started. Is this something a mechanic would have forgot to reset for oil change notice? I never reach the recommended mileage just the time frame.