I see now, too. Rig should definetly behave like before recording, so driven by the point constraint. Otherwise it will make a gap between calve and ankle joint, which leads to faulty results with the ziva sim for muscle and fat tissue.
Now i untargeted the ankle joint which resulted in this behaviour.
Guess i´ll need to untarget the rest of the hierarchy too to have the desired results?
Edit: That sadly didnt worked as expected.