My corn (about 1.5 years old) is most often on the cool side (low 70'sF) and spends time on the warm hide (85 - 88F) for a few hours each day usually for only a few days following a feedings. She's healthy as all get-out.
I have hatchling black rat snakes that hover on the hot side of their enclosure most of the time when they are not out exploring - which is pretty often for a snake - they are more diurnal and inquisitive than corns generally.
As long as your snake is eating, drinking, shedding, acting normally, and you've provided a good gradient, I wouldn't worry about any tendency to stay on the hot / cool side.