If you ever think it's a bug, make a new project and try to reproduce it.
If I make a new project, add two physics objects with different properties, then duplicate the layout, the objects on the duplicated layout preserve their same properties. So it looks like it's working fine. Perhaps there are some specific circumstances it doesn't work, but you need to be able to reproduce it in a new project so we know whether it's really a bug or not, and we can't generally fix bugs without that either.