### 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)

if (ccb) {
					binds = ccb->get_binds();
					base_callable = ccb->get_callable();
				}
				CallableCustomUnbind *ccu = dynamic_cast<CallableCustomUnbind *>(c.callable.get_custom());
				if (ccu) {
					unbinds = ccu->get_unbinds();
					base_callable = ccu->get_callable();
				}
			} else {
				base_callable = c.callable;
			}
			
			Node *common_parent = target->find_common_parent_with(p_node);
			ERR_CONTINUE(!common_parent);
			if (common_parent != p_owner && common_parent->get_scene_file_path().is_empty()) {
				common_parent = common_parent->get_owner();
			}
			bool exists = false;
			
			while (common_parent) {
				Ref<SceneState> ps;
				if (common_parent == p_owner) {
					ps = common_parent->get_scene_inherited_state();
				} else {
					ps = common_parent->get_scene_instance_state();
				}
				if (ps.is_valid()) {
					NodePath signal_from = common_parent->get_path_to(p_node);
					NodePath signal_to = common_parent->get_path_to(target);