ParallelLayout: Links are crossing nodes during animation

I use the Parallel Layout from this site.

The layout works perfekt until the animations starts.

For example:
Close the group with node U and L. When you re-open this group the link between I and L crosses the node Medium Tall Node during the animation. When the animations has finished the links jumps in the correct position.
(Same problem for example between node Another and J.)

How can I achieve a correct layout during the animation?
Do you have any hint where to start?

That is intentional behavior – it is too slow to do smart routing during animations.