Printvenue interview questions

The HR or consultant Ati Chahan called me for the skype interview but that sounds strange as the company itself is located in gurgaon so do I. The interview timings were also held at ODD timings around 8 pm in the night. the interview went well in the beginning later I was asked to find bugs in their live site. I gave them bugs (one of then was major) I was asked to wait. and then no call back from HR. later she told me they looking for other candidates as well. Why do you held the interview this way. I doubt these interview process these days as they do it just to find bugs in their sites by different QAs. Not a good experience.