### 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 _update_global_transform();
	RID texture_rid;
	DebugDraw debug_draw = DEBUG_DRAW_DISABLED;
	int positional_shadow_atlas_size = 2048;
	bool positional_shadow_atlas_16_bits = true;
	PositionalShadowAtlasQuadrantSubdiv positional_shadow_atlas_quadrant_subdiv[4];
	MSAA msaa_2d = MSAA_DISABLED;
	MSAA msaa_3d = MSAA_DISABLED;
	ScreenSpaceAA screen_space_aa = SCREEN_SPACE_AA_DISABLED;
	bool use_taa = false;
	Scaling3DMode scaling_3d_mode = SCALING_3D_MODE_BILINEAR;
	float scaling_3d_scale = 1.0;
	float fsr_sharpness = 0.2f;
	float texture_mipmap_bias = 0.0f;
	bool use_debanding = false;
	float mesh_lod_threshold = 1.0;
	bool use_occlusion_culling = false;
	Ref<ViewportTexture> default_texture;
	HashSet<ViewportTexture *> viewport_textures;
	void _update_viewport_path();
	SDFOversize sdf_oversize = SDF_OVERSIZE_120_PERCENT;
	SDFScale sdf_scale = SDF_SCALE_50_PERCENT;
	uint32_t canvas_cull_mask = 0xffffffff; 
	enum SubWindowDrag {
		SUB_WINDOW_DRAG_DISABLED,
		SUB_WINDOW_DRAG_MOVE,
		SUB_WINDOW_DRAG_CLOSE,
		SUB_WINDOW_DRAG_RESIZE,
	};
	enum SubWindowResize {