### 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)

void push_unhandled_input(const Ref<InputEvent> &p_event, bool p_local_coords = false);
#endif 
	void set_disable_input(bool p_disable);
	bool is_input_disabled() const;
	Vector2 get_mouse_position() const;
	void warp_mouse(const Vector2 &p_position);
	virtual void update_mouse_cursor_state();
	void set_physics_object_picking(bool p_enable);
	bool get_physics_object_picking();
	void set_physics_object_picking_sort(bool p_enable);
	bool get_physics_object_picking_sort();
	Variant gui_get_drag_data() const;
	void gui_reset_canvas_sort_index();
	int gui_get_canvas_sort_index();
	void gui_release_focus();
	Control *gui_get_focus_owner() const;
	PackedStringArray get_configuration_warnings() const override;
	void set_debug_draw(DebugDraw p_debug_draw);
	DebugDraw get_debug_draw() const;
	int get_render_info(RenderInfoType p_type, RenderInfo p_info);
	void set_snap_controls_to_pixels(bool p_enable);
	bool is_snap_controls_to_pixels_enabled() const;
	void set_snap_2d_transforms_to_pixel(bool p_enable);
	bool is_snap_2d_transforms_to_pixel_enabled() const;
	void set_snap_2d_vertices_to_pixel(bool p_enable);
	bool is_snap_2d_vertices_to_pixel_enabled() const;
	void set_input_as_handled();
	bool is_input_handled() const;
	void set_handle_input_locally(bool p_enable);
	bool is_handling_input_locally() const;