You apparently need an enzyme based cleaner to remove whatever it is they put into cloth to make them think they should keep coming back to it - @grievoustim too.
Now I can’t say the one our vet sold us did a lot but we had an issue with our cat shitting on the cold stone slabs next to the litter tray and the cleaner was really meant for fabrics so it’s probably that there was another explanation.
Anyway, speak to your vet.
