Ebo Jager operation??

I purchased a new Ebo Jager TS heater (250W, 105 gallon tank) - I've got the
heater set to bring the tank to 79.5 degrees - I'm used to seeing heaters
run (the red light stays on) until the tank is at the desired temp, then
cycle on and off as necessary - this heater is cycling on and off even
though the tank is not at 79.5 degrees - two different thermometers show the
tank at 77 degrees - is the heater working as designed and it'll just take
longer to get the tank to the desired temp, is does there appear to be a
problem?  Thanks!