Importing fbx asset into unity causes double vision in Mixed Reality

Hi,

Does anyone know what causes this?

I've set up a new unity 2018 project for wmr and added a block. I can see the block clearly in the headset.

Then I import an fbx object from blender 2.79 (a simple torus). Now when I view the scene again I see both the torus and the block double.

I made no other changes and the effect is reproducable from a clean project.
I'm using the samsung odyssey wmr set.

Update: removing the object brings the scene back to real 3d.
If I export the object as wavefront the issues don't arise.

 

Iam using a Dell Visor MR headset, haven't encountered any issues with blender FBX model imports in playback mode or the sideloaded app. Are you using the Mixed Reality Toolkit camera or the default Unity camera?