Are you talking about Invigorator Pro or ProAnimator? If it’s Invigorator Pro and you are using the AE timeline to animate your elements you may need to convert the drifting object’s keyframes to “Linear”. Not sure why it would be drifting in ProAnimator, perhaps you have slightly different position settings between poses…
In ProAnimator you can put objects on individual tracks by selecting the object in the Preview window and then in the timeline clicking on “Track Commands” and choosing “Move Selected Objects to Track” and choosing either an existing track or “New Object Track”.
John Dickinson
Motionworks
http://www.motionworks.com.au