I am having an issue with spring motion showing up on a simple rigged prop.  Here is what I do...

1) Drag and drop a PNG into the application, when I am prompted I select rigged prop.
2) I go into Composer and add a very basic bone chain of about five bones.
3) I go into the spring editor and add all bones starting at bone 2 to the default group.  (I start at bone 2 because I don't want it to start springing from the very first bone...)

[Note at this point the spring preview shows it to be behaving as expected.]

4) Go back to Stage Mode and select my tree, and open the 'Prop Key Editor'
5) I select bone 2 and rotate it slightly every 10 keyframes.

[Note with the Prop Key Editor open the spring effect is showing properly in real time as I rotate the bone at each keyframe.]

6) With my keyframes set up I close the Prop Key Editor
7) When I hit play the prop doesn't move at all
8) If I manually drag through the timeline I see that the rotation happens but no spring effect.

[Note if I open the Prop Key Editor again the spring effect comes back ]

I have found that with the same rig, if I keyframe the parent bone (bone 1) and just translate it around the spring animation then works fine.

Thanks