controller.render.default is broken?

[analog crane]

I'm creating a simple entity that basically is just a block so I can run some scripts off of it. It doesn't like me using the controller.render.default and keeps on coming up with an error saying Materials | friendly name 'material.default' not found in entity friendly name list (<none specified in the entity?>) - check your spelling? I'm sorry I'm new to this is there something I'm missing?

[wise rampart]

Check if the material is called default, in the client entity file

"materials": {
  "default": "entity_alphatest"
}

If the materials field does not exist, then add it