I love corn snakes. Partly because I found them fairly easy to breed, but they have plenty of other good qualities.
While my preference is to feed baby corns appropriate sized mice, my first corn snake was a six month old that had eaten about three mice in her entire life. She was starving herself to death until offered a pinkie rat. She grew up and bred for me on a rat diet. As I recall, she was never fed more than once in seven days, though. And my preference is to turn off the heat and let the temperature fall to room temperature at night, though that shouldn't make a huge difference.
I wonder if the OP's snake is using the hot spot. Factors like badly place hiding boxes might keep it in a cooler part of the cage. Or might the snake be somewhat dehydrated because it isn't using the water bowl properly? Or the snake might be trying to go into brumation. Hard to say what the exact problem is.
Good luck.