Hi!
It's just occurred to me that you are probably only seeing the viewport preview which displays segments as boxes when the object's poly counts exceeds a value set in the Display rollout. This is just to keep viewport performance fast and you should find they render absolutely fine.
If you'd like to preview the full geometry in the viewports to check they are deforming correct just go to the Display rollout and change the Viewport mode to Mesh.
I hope that helps,
Many thanks!
Paul