Summary:
When combining two shields or Trimmed Armor in a Grindstone, the output shield/Trimmed Armor will visually match the shield/Trimmed Armor in the bottom slot, which is contrary to Java. In Java, the output shield/Trimmed Armor corresponds to the shield/Trimmed Armor in the top slot.

Steps to reproduce:

1. Place the Grindstone.
2. Create 2 shields/Trimmed Armor with different banners/trims.
3. Place them in Grindstone.
4. Look at the shield banner/Trimmed Armor in the output slot.

Observed results:
In the output slot, the shield/Trimmed Armor has a banner/trim like the shield/Trimmed Armor in the bottom slot.

Expected results:
In the output slot, the shield/Trimmed Armor has a banner/trim like the shield/Trimmed Armor in the top slot.

Screenshots:
Bedrock


Java