Motion paths and timeline scrubbing issues

Storyline seems to be doing something weird where if you watch a slide through, motion paths function correctly... but, if you use the seekbar to go back to a point in the timeline before the motion path runs, the objects do not return to their original spot; they remain at the end point of the motion path.

The motion path trigger is linked to a point on the timeline (usually when an object is introduced on the timeline), so at that point, the object jumps back to its starting position and runs along the motion path as designed. The issue does not happen if you press the replay button.

I guess the problem occurs because the motion path has been triggered when you watch the slide, but there is no 'trigger' or event to tell Storyline that the object should be returned to the starting point. 

Is there a solution or workaround here? Or have I missed something blindingly obvious?! (Working in Storyline 360)

Thanks!