Difference between std::promise lvalue reference vs rvalue reference

My understanding is if we call get on future obtained from promise then it will wait till set_value is called and if that is never called program will wait forever but somehow this behavior is not working when I am using promise rvalue reference (it is throwing broken promise future error) though same is working with lvalue reference(wait forever). Any reasoning for this because i believe it should wait forever in case of rvalue reference also ?

#include <iostream>
#include <future>
#include <thread>
#include <chrono>
void calculateValue(std::promise<int> &&p)
//void calculateValue(std::promise<int> &p) //uncomment this it will wait
{
  using namespace std::chrono_literals;

  std::cout<<"This is start of thread function "<<std::endl;
  //Do long operations
  std::this_thread::sleep_for(2s);
 // p.set_value(8);
  std::cout<<"This is end of thread function "<<std::endl;

}
int main() {

  std::promise<int> p;
  auto  fut = p.get_future();
  std::thread t(calculateValue,std::move(p));
  //uncomment this it will wait
  //std::thread t(calculateValue,std::ref(p);
  std::cout<<"main function ..."<<std::endl;
  std::cout<<"value is "<<fut.get()<<std::endl;
  t.join();
  return 0;

}