We’ve got a moon surface with a lot of moon rocks and a ground surface exported as a .vrscene to use in our other scenes. If I enable use wrapper and set it to a matte surface then the particle instanced rocks (from MASH) don’t get the wrapper applied to them, but the ground surface does.
I’ve added a bug report for the developers to look at. We’ll let you know when there’s news, sorry for the inconvenience.