eco score glitch

i just started a new problem with my eco score, the graph that shows or score that shows your acceleration cruising and braking out of 100, you know how when your driving and accelerating and once you lift of the gas slightly you get a immediate score, well now at times when im driving my score will freeze, and will not move again,no matter how many times i let off the gas or even accelerate to higher speeds,i just get a frozen screen. and it will not change until i actually come to a full stop.then i start going its all back to normal changing and giving me real time scores as i drive by going slow or fast, then it freezes again on one score. and will not change. i took out my cell phone and recorded this time while it froze on a score and while driving i let off on the gas and reapplied the gas to have no change on my eco score,my car has only 20,000 km on my new 2015 prius c,trim level two.what do you think the dealer can do to resolve this issue when it sometimes does not happen say on a test drive.sure i could show him the video on my cell,but now im not so sure i want these guys playing around with my cars computer, since the last time i complained about litres per 100 score freezing up last summer at 4.7/100 while driving and not changing no matter of current speed.