I'm claiming the only consistent thing here is that the item "wave slightly" instead of having the constant effect end. That is consistent with the constant effect, the description of Wind of Mundane Silence, and with the guidelines to destroy enchantments.
The question had come up with Hermetic Projects and why the MuVi spell wouldn't be 2/day to fire off each time the spell it's affecting occurs. As you can see, the official view is it's one single effect, not one that is actually recast twice per day.
I agree that both ideas seem really dumb. But if a constant is resisted, how is it resisted without using one of these options? To avoid this, I would argue it should not be resisted by the Aegis, and if the Aegis doesn't resist it then I don't see that Parma Magica would since the Aegis covers even more than Parma Magica. The heavily implied situation that Hugh of Flambeau's item's unbreakable enchantment doesn't seem to cause the item to be resisted would be consistent with what I'm arguing. Also, this would make longevity rituals continue functioning when entering a foreign Aegis and allow those under longevity rituals to punch each other without being blocked by Parma Magica.