Importing Blender model with multiple empty material indices

I have made a simple model inside Blender. The object has two slots in the material array, both of which are empty. They can be “Assigned” as normal to the model’s different faces. The problem is that the model seems to lose the material indices, because when I set the Mesh Renderer’s material count to two and add two different materials, it just blends the two materials together and doesn’t actually place the different materials where I assigned them.

The indices are saved normally and I can check in Blender that the faces still have the correct materials assigned, but Unity seems to only let me assign separate materials if I create two different placeholder materials in Blender, even if I disable material importing. (By the way, I’d like to have all my material files in the Unity format instead of inside the Blender files.)

You could try adding temporary materials to those slots in blender before you export. That’s been working for me to solve the same issue