Many breakpoints shows when debugging

Look at code below:

#include <iostream>

int main(int argc, char *argv[])
{
    int z = 2;
    switch (z) {
    case 0:
        return 0;
    case 1:
        return 0;
    default:
        return 0;
    }

    std::cout << "123";
}

1. Put breakpoint at line "std::cout << "123";"
2. Start project with debugging (F5)
3. When breakpoint you placed will be disappeared (moved to last line) - try to put breakpoint on that line twice (click twice F9 on that line)
4. When application will be runned - you will see two breakpoints on last line. It's a bug. Press F5 three times to stop application.
5. You will see two breakpoints on line when you put just one breakpoint. It's a bug too.

I think I know what happens. See next code:

#include <iostream>

int main(int argc, char *argv[])
{
    int z = 2;
    switch (z) {
    case 0:
        return 0;
    case 1:
        return 0;
    default:
        return 0;
    }

    std::cout << "123";
    std::cout << "123";
    std::cout << "123";
}

If you put breakpoints on each line with "std::cout" and click F5 - three breakpoints moved to the last line and when application will be closed - breakpoints will be returned to their places. It's right behavior but due this mechanism I see bug I described ahead.