I have the Actia dash on my Monaco coach with the 8.1L engine. When mine would act up, it also affected the other gauges as well, including the fuel gauge.
One thing that I found would correct the issues, which only happened once or so a YEAR, was to disconnect the 12 volts at the Chassis disconnect switch for about 30 seconds. After switching the 12 volts back on, the Actia dash computer would reset and be fine for a long time. You may want to try this the next time it happens. It costs nothing and may help eliminate other items.