Even weirder is, when I export a default cube from Blender, even having read about sizes here How to import an .fbx object from Blender I dont get a cube but instead:
I don’t know about your problem, but did you try exporting GLTF instead of FBX ? It’s the recommended pipeline with Three.js, and the Blender GLTF exporter works well.
Another benefit of GLTF is that you can use DracoLoader, which is really an awesome tool as it can reduce your model size to a quarter of what it was, so the page loads are way faster.
Thanks, but after installing the package Im not sure how to reference FBXLoader. I tried var loader = new FBXLoader(); and got error Uncaught ReferenceError: FBXLoader is not defined