### 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_INDEX(p_node, nodes.size());
	ERR_FAIL_INDEX(p_name, names.size());
	ERR_FAIL_INDEX(p_value, variants.size());
	NodeData::Property prop;
	prop.name = p_name;
	if (p_deferred_node_path) {
		prop.name |= FLAG_PATH_PROPERTY_IS_NODE;
	}
	prop.value = p_value;
	nodes.write[p_node].properties.push_back(prop);
}
void SceneState::add_node_group(int p_node, int p_group) {
	ERR_FAIL_INDEX(p_node, nodes.size());
	ERR_FAIL_INDEX(p_group, names.size());
	nodes.write[p_node].groups.push_back(p_group);
}
void SceneState::set_base_scene(int p_idx) {
	ERR_FAIL_INDEX(p_idx, variants.size());
	base_scene_idx = p_idx;
}
void SceneState::add_connection(int p_from, int p_to, int p_signal, int p_method, int p_flags, int p_unbinds, const Vector<int> &p_binds) {