Anybody experiened over-qualified case

I had a phone interview with the hiring manager 2 weeks ago. He asked some technical questions and I answered all correctly. Then he said I may over qualify for the job. He told me he would bring me to an on site interview if he could adjust the open position. I felt I would not get any chance for this job.

But last week I was told to come to company for the interview on 02/03, which is yeaterday. I was little confused but happy.

Yesterday I was interviewed by 5 people including the technical leader, 2 engineers, the hiring manager and his boss (director).

The technical interview went to very well. I answered all their questions much more than their expection. The hiring manager said you have every piece we need. The technical leader really liked me. So does the director. But both engineer said I am over qualified for the job. They don't have a clear job description. Just keep ask different area questions and if I can do it.

Anybody has any idea? Thanks