A dog’s sense of smell is very strong, and although to us, cat poop smells awful, to your pooch it will probably smell like cat food or any delicious food your cat has eaten.
If they don’t get enough activity throughout the day or have no toys to play with, their noses can lead them to the litter box for some new amusement, especially if that amusement is delicious.
Change of environment, being left alone for a long period of time or loud noises - dogs deal with stress in different ways and eating poo can be one of them.