When a viewport texture is referencing a SubViewport that is the root of its own Subscene, the reference is lost when the editor is closed and reopened.
- Checkout this repo
- Open in Editor
- Save the main scene or hit "play"
- The
viewport_path
of/Node3D/BrakingReference/Sprite3D::texture
changes from "BrakingReference/SubViewport" to ".", reference is lost.