Nah. They groom one another. The cat that does the grooming is higher in hierarchy. So the other cat doesn’t want to let them, so they try to wiggle out. So the dominant cat then bites, scratches and holds on tighter and it evolves into slapping.

Also a reason why bunnies and cats are a relatively good combo. Bunnies think they are dominant when getting groomed. Cats think they dominate when grooming. Everyone’s the alpha, everyone’s happy. Just need to get the bunny used to seeing a cat.