To reproduce:

1. place a stonecutter and open its UI.
2. put a block in the crafting slot.
3. hover over and click on the recipes top and bottom pixels.
4.  notice that the wrong recipe is highlighted/selected.

There does also appears to be a difference between which recipe was highlighted by hovering, and the actual selected recipe by clicking, but they do both malfunction.

link to video: https://youtu.be/Lt8gEFYyggY