Chiseled sandstone cannot be used in a stonecutter to make sandstone slabs, even though 3 blocks of chiseled sandstone can be crafted into 6 sandstone slabs in a crafting table. The same applies to chiseled red sandstone and red sandstone slabs.
How to reproduce:
Give yourself 3 blocks of chiseled (red) sandstone.
In a crafting table, place the 3 blocks of chiseled (red) sandstone in a straight line in the crafting grid.
→ ✔ 6 (red) sandstone slabs appear in the crafting output.In a stonecutter, place one block chiseled (red) sandstone in the ingredient slot.
→ ❌ Nothing appears in the possible stonecutting output selection.
Expected result:
Chiseled (red) sandstone slabs could be converted into (red) sandstone slabs in a stonecutter, since they can in a crafting table.
Observed result:
Chiseled (red) sandstone slabs cannot be converted into (red) sandstone slabs in a stonecutter.
Can confirm. It's also worth noting that shift-clicking the item while the stonecutter GUI is open does not move the chiseled sandstone into the input slot of the stonecutter, unlike other materials such as stone.