The icky habit of poop eating is known as coprophagia (cop-ra-FAY-jee-a) and there are many suggestions on how to stop them from doing it. The only successful one I have found is to pooper scoop immediately after they go. And as you have found to block the cat box from their access. We have the baby gate raised off the floor so the cat can come an go by go under but the dogs can't.
Poop is said to have vitamins and beneficial bacteria which won't hurt them to redigest. Although I prefer mine get their goodies from food and supplements.

Poop can also contain parasite that is not good for them. When Miles was with us he would be turned out with a muzzle and poop guard if we did not have time to scoop that day.
Such a frank discussion of poop so early in the morning.
Keep posting stories on Pandy. We love to read about how they are doing.