City Job Application

I applied for and later interviewed for a city job recently. Then the next week I received a letter telling me that I had not gotten the job. So I emailed the people on the letter—asking for any helpful feedback about why I was not selected. After two days the email reply told me that they were looking for more about “project implementation;” and I had not spent any time talking about that. So I replied thanking them for the helpful feedback because indeed I had not. I also included the job description and noted for them that “project implantation” was not referenced at all (not even once) in that job description. So I wonder what the real reason was then?