Why is it that when I press the F&N keys + F6, all the vertices in the selection disappear and combine into one face?

posted to: The Subdivide Tool

I'm on a Mac, why is it that when I press the F&N keys + F6 after subdividing and with all the vertices selected, all the vertices in the selection disappear and combine into one face? The operator panel also does not show up while in this mode.