No more diarrheoa!
Suggested to try this by my vet for potential IBD diagnosis, before going down blood, urine, fecal testing route. It has cleared her up in about a week which is a huge relief. Both cats love the biscuits (nothing was wrong with the other cat but can't feed separately). I'm keeping an eye on the trays as their poop at times is more indicative of constipation but not to a point of concern.