### Godot version

4.0.3-stable

### System information

Windows 10

### Issue description

In some projects ViewportTexture remains pink and doesn't render viewport content after upgrading from 4.0.2-stable to 4.0.3-stable. If a pair of files viewport.h/viewport.cpp are downgraded back to what they were in 4.0.2-stable, problem goes away.

This is how it looks in 4.0.3-stable:
![4 0 3_stable_viewport_4 0 3](https://github.com/godotengine/godot/assets/1449921/44c191a9-4b67-4b02-90b6-4ab615f62a73)

And this is how it looks if viewport.h/viewport.cpp are downgraded back to what they were in 4.0.2-stable.
![4 0 3_stable_viewport_4 0 2](https://github.com/godotengine/godot/assets/1449921/f5abc605-f129-4222-9c0e-e9a07621dd9d)



### Steps to reproduce

Unfortunately, I cannot come up wit a simple demo project reproducing the problem. It exists in some projects and doesn't exist in others.


### Minimal reproduction project

Cannot produce a simple project reproducing the problem. In simple projects it works fine.
ERR_MAIN_THREAD_GUARD_V(nullptr);
	
	_gui_sort_roots();
	for (List<Control *>::Element *E = gui.roots.back(); E; E = E->prev()) {
		Control *sw = E->get();
		if (!sw->is_visible_in_tree()) {
			continue;
		}
		Transform2D xform;
		CanvasItem *pci = sw->get_parent_item();
		if (pci) {
			xform = pci->get_global_transform_with_canvas();
		} else {
			xform = sw->get_canvas_transform();
		}
		Control *ret = _gui_find_control_at_pos(sw, p_global, xform);
		if (ret) {
			return ret;
		}
	}
	return nullptr;
}
Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform) {