### 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.
if (p_node != this) {
		Window *w = Object::cast_to<Window>(p_node);
		if (w && (!w->is_inside_tree() || !w->is_embedded())) {
			return;
		}
		CanvasItem *ci = Object::cast_to<CanvasItem>(p_node);
		if (ci) {
			ci->queue_redraw();
		}
	}
	int cc = p_node->get_child_count();
	for (int i = 0; i < cc; i++) {
		_update_canvas_items(p_node->get_child(i));
	}
}
Ref<ViewportTexture> Viewport::get_texture() const {
	ERR_READ_THREAD_GUARD_V(Ref<ViewportTexture>());
	return default_texture;
}
void Viewport::set_positional_shadow_atlas_size(int p_size) {
	ERR_MAIN_THREAD_GUARD;
	positional_shadow_atlas_size = p_size;
	RS::get_singleton()->viewport_set_positional_shadow_atlas_size(viewport, p_size, positional_shadow_atlas_16_bits);
}
int Viewport::get_positional_shadow_atlas_size() const {