### 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)

last_color = picker->get_pick_color();
}
void EditorPropertyColor::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_ENTER_TREE:
		case NOTIFICATION_THEME_CHANGED: {
			picker->set_custom_minimum_size(Size2(0, get_theme_constant(SNAME("color_picker_button_height"), SNAME("Editor"))));
		} break;
	}
}
void EditorPropertyColor::update_property() {
	picker->set_pick_color(get_edited_property_value());
	const Color color = picker->get_pick_color();
	
	if (picker->is_editing_alpha()) {
		picker->set_tooltip_text(vformat(
				"R: %s\nG: %s\nB: %s\nA: %s",
				rtos(color.r).pad_decimals(2),
				rtos(color.g).pad_decimals(2),
				rtos(color.b).pad_decimals(2),
				rtos(color.a).pad_decimals(2)));
	} else {
		picker->set_tooltip_text(vformat(
				"R: %s\nG: %s\nB: %s",
				rtos(color.r).pad_decimals(2),
				rtos(color.g).pad_decimals(2),
				rtos(color.b).pad_decimals(2)));
	}
}
void EditorPropertyColor::setup(bool p_show_alpha) {