Perhaps the brand they had been using switched to organic? I suppose it's also possible that someone just assumed organic == better, or there were both organic

Perhaps the brand they had been using switched to organic? I suppose it's also possible that someone just assumed organic == better, or there were both organic and non-organic versions of the same cat litter, and a mix-up resulted when the premium product came up first in their search results. If they'd known what the litter would be used for, I would hope they'd have been more careful, but I don't know at what level in the supply chain the decision to switch was made.