### 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)

}
						nl = nullptr;
					} else {
						if (!nl->get_scene_file_path().is_empty()) {
							
							Ref<SceneState> state = nl->get_scene_instance_state();
							if (state.is_valid()) {
								int from_node = state->find_node_by_path(nl->get_path_to(p_node));
								int to_node = state->find_node_by_path(nl->get_path_to(target));
								if (from_node >= 0 && to_node >= 0) {
									
									if (state->is_connection(from_node, c.signal.get_name(), to_node, base_callable.get_method())) {
										exists2 = true;
										break;
									}
								}
							}
						}
						nl = nl->get_owner();
					}
				}
				if (exists2) {
					continue;
				}
			}
			int src_id;
			if (node_map.has(p_node)) {
				src_id = node_map[p_node];
			} else {
				if (nodepath_map.has(p_node)) {