Q: Faces keep turning up after naming

Even though I run through the show unnamed faces several times, and identify the people in them, the same pictures keep coming up again and again. I just ran it 5 times and the very same faces keep coming up. Some of them it guesses correctly and I accept them, others I keep entering the names. When I run it again, there they are looking for identification again!

OSx 10.8.2

Aperture 3.4.3