@burky got similar issue as yourself. I have just discovered ingnitation has to be turned off when refueling, plus I shouldn't refuel to often in small amounts and I did that a lot. Now even my tank is full on the screen one bar disappeared.
Tried to fix it disconnected battery, screen reset and even smeg reload.
Dont know what else I can do to fix it. Probably drive for a bit untill when tank will go empty and refuel again? Will it reset itself?