Continuing investigation to the root cause of #9782, while it can be temporarily fixed with a workaround.

I wrote some unit tests and debugged the zone change counter comparison between a modal double faced card and its associated permanent. See 692ec89 for details.

Normally a card that is put into a graveyard from the battlefield will have a zcc one greater than that of the permanent on the battlefield. For MDFC this is not the case. In both the simple cases of (hand -> battlefield -> graveyard) and (hand -> stack -> battlefield -> graveyard) the zcc is missing two increments. This discrepancy will compound if the card is moved around zones further.

I looked at the override in ModalDoubleFacedCard and didn't see any apparent error:

Not sure where to go from here.