I do not know anything about the Atalitalia issue. But I am interested in the solution if there is one ...
To answer Ipdenmark, I use Oculus Rift too. Here are some things I do routinely for better functioning:
1- I always close the VR mode (button on the Sketchfab viewer) before switching to another project.
2- When I just adjust one of my projects with "3D setting", usually the VR mode will not work on automatic loading. I make a detour on my Model page to display my project again.
3- If I get a stereo view after activating the Sketchfab VR mode, I have to remove my Oculus glasses, close the Oculus Deck and start the Sketchfab VR view before the oculus Deck opens again.
4- If my Oculus Touch no longer work for teleport, I restart Frirefox.