Custom Blocks are rendered too small in inventory

When using the geometry.full_block geometry identifier to make a 16x16x16 block the item appears too small compared to vanilla blocks in the inventory. A custom geometry that contains a 16x16x16 cube is also affected. This makes custom blocks feel inconsistent and out of place in the inventory.

Expected Behavior:

Custom blocks that use geometry.full_block or have a custom 16x16x16 geometry should be the same size in the inventory as vanilla blocks with the same proportions.

How to reproduce:

1. Import the attached behavior pack

2. Create a world with the behavior pack enabled

3. Compare the item size of the custom block test:fake_planks with vanilla full blocks