### 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 (reorder_from_index < 0 || is_read_only()) {
		return;
	}
	Ref<InputEventMouseMotion> mm = p_event;
	if (mm.is_valid()) {
		Variant array = object->get_array();
		int size = array.call("size");
		
		reorder_mouse_y_delta += mm->get_relative().y;
		
		
		if ((reorder_to_index == 0 && reorder_mouse_y_delta < 0.0f) || (reorder_to_index == size - 1 && reorder_mouse_y_delta > 0.0f)) {
			reorder_mouse_y_delta = 0.0f;