I really don't think anything else changed on the cat's routine. the last time this happened when my cats moved back, some years ago, she stopped doing it but now, just as I ran out of the food the went back to it. I am feeding them the standard food but I wasn't really able to afford the more twice as expensive one for kidneys that I mix with the less expensive one (it ain't really cheap) because... it is twice as expensive. almost 100 USD for two months of food. haha 🫠