### 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)

return state->can_instantiate();
}
Node *PackedScene::instantiate(GenEditState p_edit_state) const {
#ifndef TOOLS_ENABLED
	ERR_FAIL_COND_V_MSG(p_edit_state != GEN_EDIT_STATE_DISABLED, nullptr, "Edit state is only for editors, does not work without tools compiled.");
#endif
	Node *s = state->instantiate((SceneState::GenEditState)p_edit_state);
	if (!s) {
		return nullptr;
	}
	if (p_edit_state != GEN_EDIT_STATE_DISABLED) {
		s->set_scene_instance_state(state);
	}
	if (!is_built_in()) {
		s->set_scene_file_path(get_path());
	}
	s->notification(Node::NOTIFICATION_SCENE_INSTANTIATED);
	return s;
}
void PackedScene::replace_state(Ref<SceneState> p_by) {