Cats have a very keen sense of smell. Maybe the kitten doesn't like the smell of the litter. My cat didn't like the litters that claim to be odor fighters, I don't blame him, even I thought they smelled like soap. Try using plain old, unscented litter and see if that helps. When I switched litters it solved the problem. We buy the unscented litter at Petco, you can buy the tub of litter and take it back for refills at a reduced price. They have a big sandbox like structure in their stores and you just refill the container.