### 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 (expand_hovered) {
		expand_hovered = false;
		queue_redraw();
	}
	if (hovered_index != -1) {
		hovered_index = -1;
		queue_redraw();
	}
}
void EditorPropertyLayersGrid::_update_flag() {
	if (hovered_index >= 0) {
		
		
		if (value & (1 << hovered_index)) {
			value &= ~(1 << hovered_index);
		} else {
			value |= (1 << hovered_index);
		}
		emit_signal(SNAME("flag_changed"), value);
		queue_redraw();
	} else if (expand_hovered) {
		expanded = !expanded;
		update_minimum_size();
		queue_redraw();
	}
}
void EditorPropertyLayersGrid::gui_input(const Ref<InputEvent> &p_ev) {