FBX files exported from Blender are invisible if a Material is not applied?

Checking to see if anyone has seen this problem before:

I’m not exactly sure if this is a MonoGame problem, a Blender problem, a Blender plugin problem, or what exactly. This could be a misunderstanding on my part about rendering materials - I wanted to check here before reporting a bug.

To reproduce:

  • Create a Blender project with a few separate objects (IE: a few cubes).
  • Apply a Material to at least one, but not all, of the objects.
  • Export the project to an FBX file, and add the FBX to a MonoGame content project in the Pipeline tool.
  • Load the model into a MonoGame game and render it.

Expected behavior:
All objects in the Blender file are rendered in the scene.

Actual behavior:
Only the objects that had Materials applied to them in Blender are rendered.

Here’s the model in blender:

And here’s three copies of that model rendered in MonoGame:

Has anyone seen this happen before? Are Models required to have textures in order to be rendered?