Is the spring laying against the star so the star doesn't turn from vibration?
that is what I would confirm & compare the tang/teeth etc on the adjuster assy on both sides to see if they are identical (other than the mirror images/different twist on the threads). The tang somehow has to be improperly allowing the star wheel teeth to vibrate/move for it to be loosening.
live every 24 hour block of time like it's your last day on earth
