### Godot version

4.0-rc6

### System information

Fedora 37, Mesa Intel ADL GT2

### Issue description

Code that works as expected at runtime fails with Nil references to (assigned) exported vars in the editor:

![tool_global_position_error](https://user-images.githubusercontent.com/364501/222031460-ffb1ecbd-5175-4a42-8470-25285ba5f821.png)


### Steps to reproduce

Try to access the `global_position` of a `Node3D` that's assigned to an exported var.

See that it works at runtime.

See that it errors in the editor with:

> Invalid get index 'global_position' (on base: 'Nil').

### Minimal reproduction project

[tool_test.zip](https://github.com/godotengine/godot/files/10856640/tool_test.zip)

LAYER_PHYSICS_2D,
		LAYER_RENDER_2D,
		LAYER_NAVIGATION_2D,
		LAYER_PHYSICS_3D,
		LAYER_RENDER_3D,
		LAYER_NAVIGATION_3D,
		LAYER_AVOIDANCE,
	};
private:
	EditorPropertyLayersGrid *grid = nullptr;
	void _grid_changed(uint32_t p_grid);
	String basename;
	LayerType layer_type;
	PopupMenu *layers = nullptr;
	TextureButton *button = nullptr;
	void _button_pressed();
	void _menu_pressed(int p_menu);
	void _refresh_names();
protected:
	void _notification(int p_what);
	virtual void _set_read_only(bool p_read_only) override;
	static void _bind_methods();
public:
	void setup(LayerType p_layer_type);
	void set_layer_name(int p_index, const String &p_name);
	String get_layer_name(int p_index) const;
	virtual void update_property() override;
	EditorPropertyLayers();
};
class EditorPropertyInteger : public EditorProperty {