MultiplayerSpawner errors when spawning node with SubViewport

[soft-circles]

Godot version

4.0.rc1

System information

MacOS Ventura 13.1, AMD Radeon Pro 5300M, Intel UHD Graphics 630, Rendering backend: Vulkan

Issue description

When spawning a scene that contains a SubViewport within its hierarchy via a MultiplayerSpawner with a custom spawn function set via set_spawn_function(<Callable>), Godot will produce an error:

Node not found: "SubViewport" (relative to "Sprite3D").
ViewportTexture: Path to node is invalid.

The texture still gets rendered out to whatever is trying to capture the SubViewport's texture (in this case a Sprite3D) but I don't expect to see an error here because the scene hierarchy is correct even in the Remote view.

Steps to reproduce

1. Run the project
2. Notice in the Debugger the two errors that appear

main.gd Attached to the root node in the main scene calls .spawn() on the MultiplayerSpawner node. Which has subviewport_scene.tscn as the only element in it's Auto Spawn List.

In subviewport_scene.tscn There is a Sprite3D with a SubViewport as it's child. The child of the SubViewport is a full screen ColorRect.

Minimal reproduction project

spawner_error.zip

[clayjohn]

Duplicate of #27790