C++ assignment operator in while true loop and in thread doesn't work

Question

I have a thread which has while true loop and every cycle I'm assigning global variable to local variable and for some reason it doesn't work

void Loop()
{
    while (true)
    {
        std::unique_ptr<Data> data = std::make_unique<Data>();

        Mutex->Sync->lock();
        *data = *globalData;
        Mutex->Sync->unlock();

        //doing stuff
    }
}

Another loop which assigns data to global variable

void Loop2()
    {
        while (true)
        {
            std::this_thread::sleep_for(std::chrono::milliseconds(1));

            std::unique_ptr<Data> data = std::make_unique<Data>();

            //doing stuff

            data->fpsCamera = fpsCamera;
            data->localGameWorld = localGameWorld;

            Mutex->Sync->lock();
            *globalData = *data;
            Mutex->Sync->unlock();
        }
    }

I start the loop in main()

std::thread th(Loop);
th.detach();

std::thread th2(Loop2);
th2.detach();

That's what debugger says (My breakpoint is set AFTER assignment) image 1 image 2

EDIT: If I assign like that then everything works correctly:

data->fpsCamera = globalData->fpsCamera;
data->localGameWorld = globalData->localGameWorld;