Rabbits not dropping wool?

Hi all,

I'm exactly ONE item away from the full shipment achievement--I just need to sell a piece of wool, since I've apparently never shipped any.
My problem is that my rabbits haven't dropped wool in over an in-game month, all 7 of my rabbits drop rabbit's feet every 4 days. I'm at max friendship with all of them.



Is this normal? I understand that as friendship with rabbits increases, the more likely it is that they'll drop rabbit's feet instead of wool, but I don't get why that should mean they will stop dropping wool entirely. My attached image is basically what they drop every single time. It's super frustrating!