Why do I experience a second, floating body when body scanning?

When I did the 10 day Vipassana meditation retreat, sometimes I would find that when I was body scanning, I would suddenly realize I was scanning a second, floating body maybe a foot in front and above from my actual body. I could feel my sensations in the second body, but it was very disconcerting because it FELT like me, but was a projection. I felt distrustful of my own experience. If I recognized it, I could get my attention to return to my actual body and the projection would go away. What was that and why did it happen? Should I have just kept on doing what I was doing and observed, or (sort of) forcibly returned my attention to my actual body, as I did?