X Project Manager interview questions

I was first contacted by HR who asked me a few simple questions. At the end of the call, she told me that I will be contacted by the hiring manager for a phone interview. A few days later, I was contacted by the hiring manager. My conversation with her went very smooth, she was very friendly, professional. We mainly talked about my background and why I'd like to join Twitter. I was then advised that HR will get back to me. An hour later, I received an email from HR saying that the hiring manager decided that I should go to the next step in the hiring process. They scheduled 2 more phone interviews: one with a team member and one with the director (the manager of the hiring manager). Both interviews went very well. They were a bit more difficult of course, but I know they went well. After my 4th interview, they told me that my qualifications don't match :) -- which doesn't make any sense!

Applied through Linkedin. HR contacted me for the interview. I took one phone interview.