My Pidge does that but she scratches the inside of the litterbox and hardly covers anything. And she does it loudly. And long. It sounds like "Bang! Bang! Bang!" It used to make (RB) Peeka crazy and I swear you could see steam coming out of her ears, she'd get so angry! That's when she'd wait for Pidge to come out of the litterbox, then Wham! She'd pounce.