I can't tell you what's going on with the Potencia truck, but it is not completely unusual for a team to field an additional vehicle just for a very high profile race such as Daytona.
There's fixed costs to enter a vehicle; entry fee, tires, fuel, etc., so the feeling is that a one-time expenditure is offset by the greater visibility during that particular race, but can't be justified week-to-week if the truck is not generally competitive. Trucks that run at the back of the field at any track don't get a lot of TV exposure.
They may have it positioned as a back-up truck in case they crash the primary Koma truck during practice or qualifying, too.