To see this behavior, do the following -

1. Run the attached test.
2. Reduce the scale value so that Arc becomes little smaller than what was initially shown
3. Now keep moving the shear Slider from left to right and right to left
4. Do this a few times.

When the shear slider is back to initial value, I would expect the shape to be restored to it's original location. However, this does not happen and the Arc is shifting it's location and not restoring back to original position.

This appears to be intermittent so make sure you try changing the shear value a few times and keep restoring to see this.