NRVO with and without default copy constructor

Question

I make a demo code like below:

#include <iostream>
using namespace std;
class Test {
public:
    Test();
    ~Test();
    Test(const Test&);
};
Test::Test(const Test& rhs) {
    cout << "do copy constructor function" << endl;
}
Test::Test()
{
    cout << "do constructor function" << endl;
}
Test::~Test() {
    cout << "do deconstructor function" << endl;
}
Test fun1() {
    Test tmp;
    return tmp;    // NRVO
}
int main() {
    Test t1 = fun1();
    return 0;
}

I run it under VS2017 release mode, and c++ standard is set to c++17. The result is as expected, copy constructor has not been run.

But when I comment out the self-defined copy constructor and run it again:

#include <iostream>
using namespace std;
class Test {
public:
    Test();
    ~Test();
};
Test::Test()
{
    cout << "do constructor function" << endl;
}
Test::~Test() {
    cout << "do deconstructor function" << endl;
}
Test fun1() {
    Test tmp;
    return tmp;    // NRVO
}
int main() {
    Test t1 = fun1();
    return 0;
}

It turns out NRVO is invalid, because constructor runs once while deconstructor runs twice. So why would that be?