Blocks With Custom Models Don't Have Textures

Blocks that were made pre 1.16.210.50 that used custom geometry no longer have textures applied properly, I assume this is a bug relating to either the material instances or geometry component as all other custom block features still work.

Steps to Reproduce:

1. Download supplied pack

2. Give yourself the custom slab

3. It won't have a texture

Expected Results:

• Custom Blocks use textures and geometry defined in geometry and material_instances components

Actual Results:

• Blocks display 'update texture' texture