### Godot version

4.2 eca6f0e

### System information

Windows 10 x64

### Issue description


https://github.com/godotengine/godot/assets/2223172/a2796263-4e2e-4b14-a080-b3ad034cc141



### Steps to reproduce

1. Add SubViewport
2. Add Sprite2D
3. Set spirte's texture to ViewportTexture
4. Create new scene
5. Instance the new scene inside the scene with viewport
6. Make sure both scenes are opened
7. Go to instance scene and save it
8. Go to viewport scene

You will see error spam. Reloading the scene fixes it.

### Minimal reproduction project

[vip.zip](https://github.com/godotengine/godot/files/12292386/vip.zip)

VRS_DISABLED,
		VRS_TEXTURE,
		VRS_XR,
		VRS_MAX
	};
private:
	friend class ViewportTexture;
	Viewport *parent = nullptr;
	Viewport *gui_parent = nullptr; 
	AudioListener2D *audio_listener_2d = nullptr;
	Camera2D *camera_2d = nullptr;
	HashSet<CanvasLayer *> canvas_layers;
	RID viewport;
	RID current_canvas;
	RID subwindow_canvas;
	bool is_audio_listener_2d_enabled = false;
	RID internal_audio_listener_2d;
	bool override_canvas_transform = false;
	Transform2D canvas_transform_override;
	Transform2D canvas_transform;
	Transform2D global_canvas_transform;
	Transform2D stretch_transform;
	Size2i size = Size2i(512, 512);
	Size2i size_2d_override;
	bool size_allocated = false;
	RID contact_2d_debug;
	RID contact_3d_debug_multimesh;
	RID contact_3d_debug_instance;
	Rect2 last_vp_rect;
	bool transparent_bg = false;