Cant put curse of binding on carved pumpkin, only on normal pumpkin

Beeing unable to put Curse of Binding on a carved pumpkin

What I expected to happen was...:
The enchantement should go on the carved pumpkin

What actually happened was...:
The enchantment still goes onto the normal pumpkin

Steps to Reproduce:
1. Get a Curse of Binding book
2. Get a normal and a carved pumpkin
3. Get an anvil
4. Go to survival mode
5. Try to put the enchanted book on both pumpkins