Starting a terminal application multiple times can get unexpected input

Switch to using Terminal.app / external terminal.

Use a console app that reads input from cin, like

#include <iostream>
#include <string>

int main(int argc, char *argv[])
{
    std::string s;
    std::cout << "Enter something: ";
    std::cin >> s;
    std::cout << "You entered: " << s << std::endl;
    return 0;
}

Start it multiple times without closing the old instance.

Sometime the application prints "You entered: echo", and closes