### 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)

Control *mouse_over = nullptr;
		Window *subwindow_over = nullptr; 
		Window *windowmanager_window_over = nullptr; 
		Control *drag_mouse_over = nullptr;
		Vector2 drag_mouse_over_pos;
		Control *tooltip_control = nullptr;
		Window *tooltip_popup = nullptr;
		Label *tooltip_label = nullptr;
		Point2 tooltip_pos;
		Point2 last_mouse_pos;
		Point2 drag_accum;
		bool drag_attempted = false;
		Variant drag_data;
		ObjectID drag_preview_id;
		Ref<SceneTreeTimer> tooltip_timer;
		double tooltip_delay = 0.0;
		bool roots_order_dirty = false;
		List<Control *> roots;
		HashSet<ObjectID> canvas_parents_with_dirty_order;
		int canvas_sort_index = 0; 
		bool dragging = false;
		bool drag_successful = false;
		bool embed_subwindows_hint = false;
		Window *subwindow_focused = nullptr;
		Window *currently_dragged_subwindow = nullptr;
		SubWindowDrag subwindow_drag = SUB_WINDOW_DRAG_DISABLED;
		Vector2 subwindow_drag_from;
		Vector2 subwindow_drag_pos;
		Rect2i subwindow_drag_close_rect;
		bool subwindow_drag_close_inside = false;