I thought of a UTI, but the vet checked yesterday and she's healthy. I've turned it off for now (it looks like she'll go in it as long as she see's Mau going in and it doesn't go off) and this weekend I'm planning to switch back to their old one. I thought the auto was a good idea, but she seems to have other ideas. Now I just have to tell Mau, she'll come running to watch it go off as strange as that sounds , but Emma won't use a different litter box so I'll have to switch them both. Thanks everyone!