Look at the little Video. I can’t quite understand, why the Breath Mark isn’t moving, when switching off the property?!?
It seems like a little invalidation bug to me. I suspect if you were to make a selection in the music and e.g. adjust the pitch of a note in that bar, you would see the breath mark jump back to its default position without having to switch the property back again. I expect we’ll be able to address this at some point in the near future.