In need of someone with FBX to Amnesia experience.

[Mudbill]

There was an update after 1.3, which was 1.3.1. That one managed to break skyboxes, and to fix it you still have to replace a .dll file in your game dir. It's entirely possible they broke more than just the skybox in 1.3.1.

I don't know about the invisible material, but the scaling might be fixed by deleting the .msh file and loading it a second time in the ModelViewer. I've had this issue with most models I export (although .dae) where the first .msh file fails to shape the model correctly. Not sure why, but worth a try I guess.