I had a background check once. They asked for my dates of attendance at my alma mater, which I provided. Then they called for clarification, because the dates they got from the university didn't match - I took 4 years to do a 4 year degree, graduating in 2009, but somehow the information they got suggested that I started in August 2007 and "left" in October 2008 - although they did agree that I had a degree.

I tried to explain to them that the dates they had managed to get from the university were for a job I had on campus, and that I hadn't done a bachelor's in a year. "Yes, sir, but if I can just confirm that you were there August 2007 through October 2008, then this will clear things up." So I did the expedient thing.