Non moving skeletons.

When ever I enter the following command:
/tp @e X Y Z
I get a random number of skeletons that won't move and that cannot be killed.
It doesn't matter where I teleport them to. I believe this may be in reference to the new skeleton jockey?
My only solution thus far to get rid of them, is to teleport them bellow the void.
Or If I move far enough away to allow them to despawn.