I have been getting the same bug with cooking. I think it is an actual bug because it is happening with one item in particular (walnuts) that I haven’t cooked with ever. I was so excited to find this new item, and then when I went back to cook with it, it wasn’t showing up in discovery. Since I haven’t ever cooked with walnuts before (or even seen a recipe that used them), it isn’t possible that there just aren’t any new recipes for me to find.
I have also not been able to use blueberries in discovery, and probably other items as well.