Sometimes when you try to create a subfile from 3D selection, it fails... I noticed that a while ago, but couldn't reproduce the problem reliably. It seems that I finally got a useful sample!
Short video showing the problem
https://youtu.be/w_8RwK327vQ
Attached file below.
Short video showing the problem
https://youtu.be/w_8RwK327vQ
Attached file below.