This sounds more like Fuel Maintenance Mode. Once the average age of the gas in the tank reaches one year the car will switch to being a hybrid and burn all the gas in the tank. There are two ways to resolve this:
1) Keep your battery full and let the car run the tank dry. If you do this you'll enter reduced propulsion mode where the car won't generate more than 50KW of power to preserve the battery until you can get to a gas station. Put in three gallons (per the owners manual)
or (better way is #2)
2) Keep your battery full and run the tank to the "LOW" warning. This occurs when you have about 3/4 of a gallon left in the tank. Put three gallons of gas back into the tank. The reason you want a full battery here is just in case you don't get to a gas station before encountering scenario #1.
In either case it sounds like you don't use gas enough to justify carrying around a full tank of gas. So do what the owners manual says in this situation and put in three gallons to reset the fuel age calculator.