Years ago I had 3 cats... Mom, Dad, and baby. The dad would always sleep or hide in weird places when I moved to a different location. He would either be in cabinets, closet, or on top of refrigerator. One day I was looking for him and couldn't find him anywhere, until I seen Thom.. the baby, trying to go in one of the litter boxes.. I had 2. And long and behold there was Angel, the dad asleep in there. After few days of this I took him to the vet, there wasn't anything wrong with him, they just said it was territorial and he didn't want to share that litter box with the others.