I've seen some strange behavior as well, it seems inconsistent, but I'm not sure if it actually is. Different skills might wear off at different times.
I've seen enemies Knocked down by my Knight, whose turn comes immediately after my Knight, getting up immediately. It costs them their turn, but they didn't spend a full turn on the ground until my Knight's turn came back around, and I rather think that they should have.
Same with the Dwarf's Petrifying Touch.
