### 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)

ERR_FAIL_COND_V(p_node < 0, false);
	if (p_node < nodes.size()) {
		const StringName *namep = names.ptr();
		for (int i = 0; i < nodes[p_node].groups.size(); i++) {
			if (namep[nodes[p_node].groups[i]] == p_group) {
				return true;
			}
		}
	}
	if (base_scene_node_remap.has(p_node)) {
		return get_base_scene_state()->is_node_in_group(base_scene_node_remap[p_node], p_group);
	}
	return false;
}
bool SceneState::disable_placeholders = false;
void SceneState::set_disable_placeholders(bool p_disable) {