### 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;
	if (camera_3d_override) {
		camera_3d_override.transform = p_transform;
		RenderingServer::get_singleton()->camera_set_transform(camera_3d_override.rid, p_transform);
	}
}
Transform3D Viewport::get_camera_3d_override_transform() const {
	ERR_READ_THREAD_GUARD_V(Transform3D());
	if (camera_3d_override) {
		return camera_3d_override.transform;
	}
	return Transform3D();
}
Ref<World3D> Viewport::get_world_3d() const {
	ERR_READ_THREAD_GUARD_V(Ref<World3D>());
	return world_3d;
}
Ref<World3D> Viewport::find_world_3d() const {
	ERR_READ_THREAD_GUARD_V(Ref<World3D>());
	if (own_world_3d.is_valid()) {
		return own_world_3d;
	} else if (world_3d.is_valid()) {
		return world_3d;
	} else if (parent) {
		return parent->find_world_3d();
	} else {
		return Ref<World3D>();
	}
}
void Viewport::set_world_3d(const Ref<World3D> &p_world_3d) {