I had this happen yesterday, also, for Sparkle Powder, a Crystalmalizer, and Carrots. Reloading fixed the problem, but it would reoccur later with a different item. I submitted an auto-bug through the game if that helps, dev-types.
I've seen this for several items at random. Based on how grain looks when it happens to it, I think it is showing the pic of what it looks like when it's on the ground, rather than what it should look like in your bag. Refreshing usually solves it.